Daily Review Applying Newton's 1st Law PDF

Daily Review Reminder: An object’s motion will not change unless it is acted Applying Newton’s 1st Law on by an external unbalanced force. 1....

Daily Review Reminder: An object’s motion will not change unless it is acted Applying Newton’s 1st Law on by an external unbalanced force. 1. Describe the motion of the object (at rest or moving). 2. Identify the unbalanced force (if any). 3. Describe the change to the motion of the object (if any). How does Newton’s 1st Law apply in the following situation? 1. You, your glass, and your water are in a state of motion. You are walking with 2. There is an external a full glass of water unbalanced force applied when you stop to you and your glass, but suddenly to avoid not your water. running into someone. Some of 3. You and your glass come to your water splashes a stop, but the water out of your glass. continues to move.  CFU 1 Daily Review What is Newton’s 3rd Law? Newton’s 3rd Law Newton’s 3rd Law states that: If object A pushes / pulls object B (action force), object B will push / pull object A an equal amount Reaction Action in the opposite direction (reaction force). The starting blocks push The sprinter’s foot pushes back on the sprinter’s foot on the blocks For example, a sprinter pushes on the starting blocks, which is the action force. CFU 2 The reaction force is the starting blocks How does Newton’s 3rd Law apply to a nail pushing back on the sprinter, propelling being hit with a them forwards. hammer? (Think: what is the action force and what is the reaction force? Which objects are they being applied to?) Daily Review Applying Newton’s 3rd Law 1. Draw a diagram of the situation, including forces. 2. Label and describe the action and reaction forces. The table pushes Reaction How does Newton’s 3rd Law apply in back on the book the following situation? Action The weight force of A book resting on a table exerts its the book pushes on weight force onto the table. The table the table exerts an equal force on the book. Daily Review Applying Newton’s 3rd Law 1. Draw a diagram of the situation, including forces. 2. Label and describe the action and reaction forces. How does Newton’s 3rd Law apply in the following situation? The air is pushed out of the balloon A balloon car is propelled forwards by the air escaping from the balloon. Reaction The air pushes the car forwards Newton’s 2nd Law of Motion Year 10 Physics Learning Intention We are learning how Newton's Laws apply in real-world situations. Success Criteria I can define net force. CFU What are we going to I can explain the relationship between force, mass, and learn? acceleration. I can distinguish between mass and weight. I can perform calculations using Newton’s 2nd law (F = m × a). Activate Prior Knowledge Acceleration is the rate of change in velocity of an object (i.e. how quickly it is speeding up or slowing down). Think, Pair, Share: If the two trucks pictured have the same engine, which one will be able to accelerate from rest to its top speed first? Explain your choice.  CFU 1 Concept Development What is the net force in Net Force the image on the right? The net force (a.k.a. total force) on an object is the sum of CFU 2 all the forces acting on it. What is the net force in Forces in the same direction are added together. the middle image? Forces in the opposite direction are subtracted. Forces are vector quantities, so they need to be written with a direction. They are measured in newtons (N).  CFU 1 Concept Development What two variables Newton’s 2nd Law does acceleration depend on? Newton’s 2nd Law states that the acceleration of an object CFU 2 depends on two variables: What equation can be The net force acting on the object used to relate force, The mass of the object mass and acceleration? CFU 3 If a 2 kg mass is The relationship between force, mass and acceleration can accelerated at 5 m/s2, represented by the equation what force, in newtons, is required? F=m×a Where F = net force in Newtons (N) m = mass in kilograms (kg) a = acceleration in metres per second per second (m/s2) NB: you cannot use different units  CFU 1 Concept Development How is the force acting Newton’s 2nd Law on an object related to its acceleration? The acceleration of an object depends directly on the force CFU 2 acting on the object. Which train will have a As the force acting on the object increases, the acceleration higher acceleration? Explain your choice. of the object is increased. Doubling the force doubles the acceleration. CFU 3 If each engine produces the same amount of force, the acceleration Small force gives small acceleration of the second train will be ___________ the acceleration of the first. Large force gives large acceleration  CFU 1 Concept Development How is the mass of an Newton’s 2nd Law object related to its acceleration? The acceleration of an object depends inversely on the mass CFU 2 of the object. Which train will have a As the mass of the object increases, the acceleration of the higher acceleration? Explain your choice. object is decreased. Doubling the mass halves the acceleration. CFU 3 If each engine produces the same amount of force, the acceleration Smaller mass gives larger acceleration of the second train will be ___________ the acceleration of the first. Larger mass gives smaller acceleration Vocabulary inversely (adjective) having the opposite effect  CFU 1 Concept Development What is the definition of Mass and Weight weight in physics, and what units do we use? In everyday speech, we use the words ‘weight’ and ‘mass’ CFU 2 interchangeably. In physics, they mean different things. If an object has a weight Weight is the force of gravity acting on an object. of 600 N, what is its Since weight is a force, it is measured in newtons (N). approximate mass? Mass is the amount of matter in an object CFU 3 Acceleration due to (measured in kg). gravity on the moon is On Earth, the acceleration due to gravity (g) is 9.8 m/s2. 1.6 m/s2. Would the weight of an object An object with a mass of 20 kg increase, decrease or will have a weight of 196 N. remain the same on the moon? Explain your choice. Skill Development / Guided Practice Comparing Acceleration Using Newton’s 2nd Law 1. Identify whether the mass or force is changing. 2. Describe the acceleration of the objects. How does Newton’s 2nd Law apply in 1. The force acting on the object is the following situation? changing. 2. The trolley will accelerate at a higher A person pulls a single trolley along rate when pulled with more force. the ground. Two people pull the trolley together. Skill Development / Guided Practice Comparing Acceleration Using Newton’s 2nd Law 1. Identify whether the mass or force is changing. 2. Describe the acceleration of the objects. How does Newton’s 2nd Law apply in 1. The mass of the object is changing. the following situation? 2. The trolley with more mass will accelerate at a lower rate when A person pulls a single trolley along pulled with the same force. the ground. The mass of the trolley is doubled. Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. What force is required to accelerate a 6 kg mass at 2 m/s2 west? F=? F=m×a F=6×2 The force required m = 6 kg is 12 N west. a = 2 m/s2 west F = 12 N Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. A force of 10 N south is applied to a 2 kg mass. What is the acceleration of the object? F = 10 N south F=m×a 10 The object accelerates a= m = 2 kg 2 at 5 m/s2 south. a=? F a= a = 5 m/s2 south m Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. Acceleration due to gravity is 9.8 m/s2 downwards. What is the weight force of a 5 kg object? F=? F=m×g F = 5 × 9.8 The weight force is m = 5 kg 49 N downwards. g = 9.8 m/s2 downwards F = 49 N Relevance Understanding Newton’s 2nd Law will help you understand why objects with a large mass require more force to accelerate or decelerate. It will also help you understand why more force is required to make objects accelerate at a higher rate. Skill Closure What equation is used to represent Newton’s 2nd Law of motion? Skill Closure How is mass different to weight? Skill Closure Which rock requires more force to accelerate? Explain your choice. Comparing Acceleration Using Newton’s 2nd Law 1. Identify whether the mass or force is changing. 2. Describe the acceleration of the objects. Independent Practice Complete Stile Lesson 3.3 or the Newton’s 2nd Law Worksheet. Daily Review Newton’s 1st Law Newton’s 1st Law states that: An object will not change its motion unless acted on by an external unbalanced force. Think, Pair, Share: Describe an example of how Newton’s 1st Law applies to objects that aren’t moving. Think, Pair, Share: Describe an example of how Newton’s 1st Law applies to moving objects. Daily Review Reminder: An object’s motion will not change unless it Applying Newton’s 1st Law is acted on by an external unbalanced force. 1. Describe the motion of the object (at rest or moving). 2. Identify the unbalanced force (if any). 3. Describe the change to the motion of the object (if any). How does Newton’s 1st Law apply in the following situation? 1. The space probe is in constant motion. 2. There is no force being NASA’s New Horizons applied to the probe. space probe is more than 7.5 billion km from 3. The space probe will Earth and is moving remain in constant motion away from us at without changing velocity. approximately 53,000 km/h. Daily Review Reminder: An object’s motion will not change unless it Applying Newton’s 1st Law is acted on by an external unbalanced force. 1. Describe the motion of the object (at rest or moving). 2. Identify the unbalanced force (if any). 3. Describe the change to the motion of the object (if any). How does Newton’s 1st Law apply in the following situation? 1. The bike and person are in a state of motion. 2. There an external unbalanced force A person goes over the handlebars of applied to the bike, but not the their bike when they hit something in person. the road. 3. The bike will come to a stop, while the person will continue to move. Newton’s 3 rd Law of Motion Year 10 Physics Learning Intention We are learning how Newton's Laws apply in real-world situations. Success Criteria I can identify action and reaction forces. CFU What are we going to I can state Newton’s 3rd Law of Motion. learn? Activate Prior Knowledge What happens to a balloon when you blow it up and then release it without tying it? What would happen if you blew the balloon up to a large volume compared to a small volume?  CFU 1 Concept Development When the air is pushed Action-Reaction Forces out of a balloon, the balloon is pushed Isaac Newton realised that forces always occur in pairs. forward. In this situation, what is If a tennis ball is hit by a racquet, the the action force? racquet applies a force to the ball and CFU 2 the ball accelerates forward. In this situation, what is This is called an action force. the reaction force? However, the ball also exerts a force back onto the racquet, which you can feel as you hit the ball. This is called a reaction force.  CFU 1 Concept Development What is Newton’s 3rd Law? Newton’s 3rd Law Newton’s 3rd Law states that: If object A pushes / pulls object B (action force), object B will push / pull object A an equal amount Reaction Action in the opposite direction (reaction force). The starting blocks push The sprinter’s foot pushes back on the sprinter’s foot on the blocks For example, a sprinter pushes on the starting blocks, which is the action force. CFU 2 The reaction force is the starting blocks How does Newton’s 3rd Law apply to a nail pushing back on the sprinter, propelling being hit with a them forwards. hammer? (Think: what is the action force and what is the reaction force? Which objects are they being applied to?) Skill Development / Guided Practice Applying Newton’s 3rd Law 1. Draw a diagram of the situation, including forces. 2. Label and describe the action and reaction forces. The table pushes Reaction How does Newton’s 3rd Law apply in back on the book the following situation? Action The weight force of A book resting on a table exerts its the book pushes on weight force onto the table. The table the table exerts an equal force on the book. Skill Development / Guided Practice Applying Newton’s 3rd Law 1. Draw a diagram of the situation, including forces. 2. Label and describe the action and reaction forces. How does Newton’s 3rd Law apply in the following situation? The water pushes the A octopus squirts water out of a tube octopus forwards near its head. The water pushes back The octopus pushes on the octopus, propelling it in the water backwards opposite direction. Skill Development / Guided Practice Applying Newton’s 3rd Law 1. Draw a diagram of the situation, including forces. 2. Label and describe the action and reaction forces. How does Newton’s 3rd Law apply in the following situation? A skateboarder pushes on the ground, which make them move Action forwards. The ground pushes The boy’s foot back on the boy’s foot pushes the ground Skill Development / Guided Practice Applying Newton’s 3rd Law 1. Draw a diagram of the situation, including forces. 2. Label and describe the action and reaction forces. An explosion pushes the ball out of the cannon The ball pushes back on the How does Newton’s 3rd Law apply in cannon, so it rolls backwards the following situation? A cannonball is shot out of a cannon, causing the cannon to roll backwards. Relevance Understanding Newton’s 3rd Law will help you understand why we are able to move by walking and jumping. It will also help you understand how rockets and jet engines are able to move objects in space, and why objects like cannons and guns recoil when something is shot out of them. Skill Closure What is Newton’s 3rd Law of Motion? Skill Closure When a rocket launches, gases are pushed out the bottom of the rocket, which propels the rocket upwards. Draw a diagram and label the forces involved in a rocket launching. Independent Practice Complete Stile Lesson 2.2 or the Newton’s 3rd Law Worksheet. Newton’s 1 st Law of Motion Year 10 Physics Learning Intention We are learning how Newton's Laws apply in real-world situations. Success Criteria I can state Newton’s 1st Law of Motion. CFU What are we going to I can define inertia. learn? I can apply Newton’s 1st Law to stationary and moving objects. Activate Prior Knowledge A force is any push or pull that happens when two objects interact. Forces can make objects: Change speed Change direction Change shape Think, Pair, Share: Describe an example of a force that causes each type of change.  CFU 1 Concept Development How does Newton’s 1st Newton’s 1st Law Law apply to objects that aren’t moving? Newton’s 1st Law states that: CFU 2 An object will not change its motion unless How does Newton’s 1st acted on by an external unbalanced force. Law apply to objects In other words: things like to keep doing what they’re that are moving? already doing. CFU 3 Why does a ball eventually stop after For example, a plant at rest (not moving) on a table will you have kicked it? stay at rest until an outside force moves it. An ice hockey puck sliding on the ice will keep sliding until it is stopped by an outside force.  CFU 1 Concept Development What is the other name Inertia for Newton’s 1st Law? Newton’s 1st Law is also called the Law of Inertia. CFU 2 Inertia is the tendency of an object to resist changes to its What is inertia? motion. CFU 3 If the object is at rest, it ‘wants’ to stay at rest. Why do you move Likewise, if it is moving, it ‘wants’ to keep moving. forward when a car brakes suddenly? When you are moving in a car and it brakes, the friction of the brakes stops the car, but does not stop you. Your body keeps moving forward until stopped by your seatbelt. (or the seat in front of you… or the windshield… or worse!)  Reminder: CFU 1 Concept Development How does mass affect Inertia is the tendency of an object to Inertia resist changes to its motion. inertia? An object with a larger mass has more inertia than an object CFU 2 with a smaller mass. Which will have more inertia: an empty shopping trolley or a full For example, a bowling ball has more inertia than a netball shopping trolley? Explain your choice. because it has more mass. Even though they are a similar size, it takes more force to move the bowling ball than the netball because it has more mass. It also takes more force to stop the bowling ball once it is moving than it would take to stop a netball moving at the same speed. Skill Development / Guided Practice Reminder: An object’s motion will not change unless it Applying Newton’s 1st Law is acted on by an external unbalanced force. 1. Describe the motion of the object (at rest or moving). 2. Identify the unbalanced force (if any). 3. Describe the change to the motion of the object (if any). How does Newton’s 1st Law apply in 1. The soccer ball is at rest. the following situation? 2. The player is applying an unbalanced force to the ball. A soccer ball sitting on the ground is 3. The force applied to the ball will kicked by a player. cause it to move. Skill Development / Guided Practice Reminder: An object’s motion will not change unless it Applying Newton’s 1st Law is acted on by an external unbalanced force. 1. Describe the motion of the object (at rest or moving). 2. Identify the unbalanced force (if any). 3. Describe the change to the motion of the object (if any). How does Newton’s 1st Law apply in 1. The soccer ball is moving. the following situation? 2. The net is applying an unbalanced force to the ball. A soccer ball moving through the air 3. The force applied to the ball will stops when it hits the net at the back cause the ball to slow down and of the goal. stop. Skill Development / Guided Practice Reminder: An object’s motion will not change unless it Applying Newton’s 1st Law is acted on by an external unbalanced force. 1. Describe the motion of the object (at rest or moving). 2. Identify the unbalanced force (if any). 3. Describe the change to the motion of the object (if any). How does Newton’s 1st Law apply in 1. The space probe is in the following situation? constant motion. NASA’s New Horizons 2. There is no force being space probe is more than applied to the space probe. 7.5 billion km from 3. The space probe will Earth and is moving remain in constant motion away from us at without changing velocity. approximately 53,000 km/h. Skill Development / Guided Practice Reminder: An object’s motion will not change unless it Applying Newton’s 1st Law is acted on by an external unbalanced force. 1. Describe the motion of the object (at rest or moving). 2. Identify the unbalanced force (if any). 3. Describe the change to the motion of the object (if any). How does Newton’s 1st Law apply in 1. The tablecloth and glassware are in the following situation? a state of rest. A tablecloth is pulled out from 2. There an unbalanced force applied underneath some glassware. to the tablecloth, but not the glassware. 3. The tablecloth will move from underneath the glassware, but the glassware remains at rest. Relevance Understanding Newton’s 1st Law will help you understand why objects that are stationary will remain so until an external force causes them to move. It will also help you understand why objects will keep moving until a force causes a change in their motion. Knowing about inertia will help you understand why objects with a small mass are easier to move or stop than objects with a large mass. Skill Closure What is Newton’s 1st Law of motion? Reminder: Inertia is the tendency of an object to resist changes to its motion. Skill Closure How does mass affect the inertia of an object? Skill Closure Watch the clip and explain how Newton’s 1st Law applies. Independent Practice Complete Stile Lesson 1.2 or the Newton’s 1st Law Worksheet. Daily Review Newton’s 1st Law Newton’s 1st Law states that: An object will not change its motion unless acted on by an external unbalanced force. A simple way to think about this is that objects like to keep doing what they’re already doing. Daily Review Reminder: An object’s motion will not change unless it Applying Newton’s 1st Law is acted on by an external unbalanced force. 1. Describe the motion of the object (at rest or moving). 2. Identify the unbalanced force (if any). 3. Describe the change to the motion of the object (if any). How does Newton’s 1st Law apply in 1. The skydiver is in motion. the following situation? 2. The forces being applied to the skydiver are balanced. After falling for 12 seconds, a skydiver 3. The skydiver will remain in is moving so quickly that constant motion without the force provided by air changing velocity. resistance is equal to the force provided by gravity. Daily Review Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. A 2 kg book is placed on a shelf 2.5 m above the ground. What is its gravitational potential energy? 𝑚 = 2 kg 𝐸p = 𝑚𝑔ℎ 𝐸p = 2 × 9.8 × 2.5 The book has 49 J of ℎ = 2.5 m 𝐸p = 49 gravitational potential 𝑔 = 9.8 m/s2 energy. 𝐸p = ? Daily Review Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. You are standing on the top of a 25 m high hill. Your gravitational potential energy is 17150 J. What is your mass? 𝑚=? 𝐸p = 𝑚𝑔ℎ 17150 𝑚= 9.8 × 25 ℎ = 25 m Your mass is 70 kg. 𝑔 = 9.8 m/s2 𝐸p 17150 𝑚= 𝑚= 245 𝐸p = 17150 J 𝑔ℎ 𝑚 = 70 Daily Review Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. An object is thrown straight up into the air at a velocity of 10 m/s. If its mass is 2 kg, how much kinetic energy does it have at the peak of its flight? 𝑣 = 0 m/s 1 2 1 𝐸k = 2 𝑚𝑣 𝐸k = × 2 × 02 The object has 0 J of 𝑚 = 2 kg 2 kinetic energy at the peak 𝐸k = ? 𝐸k = 0 of its flight. Kinetic and Potential Energy Calculations, Pt. 2 Year 10 Physics Learning Intention We are learning about mechanical energy and how it can be transformed. Success Criteria I can describe how energy is transformed as an object falls. I can apply my understanding of energy transformations to calculations involving energy, velocity, mass, and height. CFU What are we going to learn?  CFU 1 Activate Prior Knowledge What is the law of As an object falls, its gravitational potential energy is conservation of energy? transformed into kinetic energy. CFU 2 The total amount of energy always remains the same – What happens to an object’s gravitational energy is never created or destroyed. This is called the potential energy as it law of conservation of energy. falls?  CFU 1 Concept Development Why does an object lose Energy Transformations in Falling Objects GPE as it falls? As an object falls (or rolls down a slope), its gravitational CFU 2 potential energy is transformed into kinetic energy. What happens to an object’s kinetic energy It loses height (↓ℎ → ↓𝐸p) and speeds up (↑𝑣 → ↑𝐸k ). as it rises, and why? Reminder When an object rises, its kinetic energy is transformed into 1 𝐸k = 𝑚𝑣 2 gravitational potential energy. 2 It slows down (↓𝑣 → ↓𝐸k ) and gains height (↑ℎ → ↑𝐸p). 𝐸p = 𝑚𝑔ℎ Its total energy always remains the same: 𝐸total = 𝐸k + 𝐸p  CFU 1 Concept Development When does a falling Energy Transformations in Falling Objects object have: a) maximum GPE? At a falling object’s highest point, it has maximum b) maximum kinetic gravitational potential energy and no kinetic energy. energy? When an object reaches the ground, all of that potential CFU 2 energy has been transformed into kinetic energy: Halfway to the ground, the ball has 50 J of 𝐸p = 𝐸k top bottom gravitational potential energy. What is its kinetic energy at this Ep = 50 J point in its fall? Ek = ? J Ep = 100 J Etotal = 100 J Reminder Ek = 0 J The total amount of Etotal = 100 J energy always remains Ep = 0 J the same – energy is Ek = 100 J never created or Etotal = 100 J destroyed. Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. Reminder: 𝐸p = 𝐸k top bottom A 0.5 kg book is sitting on a shelf 2 m from the ground. If it falls, how much kinetic energy will it have when it reaches the ground? 𝑚 = 0.5 kg 𝐸p = 𝑚𝑔ℎ 𝐸p = 0.5 × 9.8 × 2 ℎ=2m top 𝑔 = 9.8 m/s2 𝐸p = 9.8 The book has 9.8 J of 𝐸p = 𝐸k top top kinetic energy when it bottom 𝐸k = 9.8 reaches the floor. bottom Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. Reminder: 𝐸p = 𝐸k top bottom A 10 kg mass is dropped from a height. It has 196 J of kinetic energy when it reaches the ground. From what height is it dropped? 𝐸p = 𝑚𝑔ℎ 196 The mass is ℎ= 𝑚 = 10 kg 10 × 9.8 dropped ℎ=? 𝐸p from 2 m. 𝑔 = 9.8 m/s2 ℎ= 196 𝑚𝑔 ℎ = 98 𝐸k = 196 J = 𝐸p bottom top ℎ=2 Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. Reminder: 𝐸p = 𝐸k top bottom A rock with a mass of 8 kg rolls down a hill. At the bottom of the hill it has a velocity of 5 m/s. How much gravitational potential energy did it have at the top of the hill? 1 𝐸k = × 8 × 52 1 2 𝑚 = 8 kg 𝐸k = 𝑚𝑣 2 𝑣 = 5 m/s 2 𝐸k = 4 × 25 𝐸p = 𝐸k 𝐸k = 100 J top bottom The rock had 100 J of bottom gravitational potential 𝐸p = 100 J top energy. Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. Reminder: A ball with a mass of 2 kg is thrown 𝐸p = 𝐸k into the air at an initial velocity of top bottom 10 m/s. What will be the ball’s 𝐸 = 1 𝑚𝑣 2 maximum height? k 2 𝐸p = 𝑚𝑔ℎ 1 𝐸k = × 2 × 102 𝑚 = 2 kg 2 𝐸p 𝑣 = 10 m/s 𝐸k = 1 × 100 ℎ= 𝑚𝑔 The ball will reach a ℎ=? 𝐸k = 100 J 100 height of 5.1 m above 𝑔 = 9.8 m/s2 bottom ℎ = 2 × 9.8 the person’s hand. 𝐸k = 𝐸p 𝐸p = 100 J bottom top top ℎ = 5.1 m Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 1 2 𝐸k = 2 𝑚𝑣 4. Write the final answer with appropriate units and direction. 2 Challenge Question 2𝐸k = 𝑚𝑣 Winnie the Pooh drops a 10 g stick off a 2𝐸k bridge. How fast is the stick moving = 𝑣2 when it hits the water 3 m below? 𝑚 𝐸p = 𝑚𝑔ℎ 𝑚 = 10 g = 0.01 kg 2𝐸k 𝐸p = 0.01 × 9.8 × 3 𝑣= The stick is moving at 𝑣=? 𝑚 7.67 m/s. ℎ=3m 𝐸p = 0.294 J 𝑔 = 9.8 m/s2 top 2 × 0.294 Reminder: 𝐸p = 𝐸k 𝐸k = 0.294 J 𝑣= top bottom bottom 0.01 𝐸p top = 𝐸k bottom Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. Challenge Question – Alternate Solution Winnie the Pooh drops a 10 g stick off a bridge. How fast is the stick moving when it hits the water 3 m below? 𝐸p = 𝐸k 𝑣 = 2𝑔ℎ 𝑚 = 10 g = 0.01 kg top bottom 𝑣=? 1 𝑣 = 2 × 9.8 × 3 The stick is moving at 𝑚𝑔ℎ = 𝑚𝑣 2 7.67 m/s. ℎ=3m 2 𝑣 = 7.67 1 2 𝑔 = 9.8 m/s2 𝑔ℎ = 𝑣 Reminder: 2 2 𝐸p = 𝐸k 2𝑔ℎ = 𝑣 top bottom Relevance Understanding the relationship between gravitational potential energy and kinetic energy allows you to predict many aspects of an object’s motion. This is important in the design of vehicles and sporting equipment, military applications, and much more. Skill Closure Explain the law of conservation of energy. Skill Closure Write the equations used to calculate the gravitational potential energy and the kinetic energy of an object. What is the relationship between these quantities? Reminder: Skill Closure 𝐸p = 𝐸k A box with a mass of 4 kg is placed on a coffee table that is 1 m top bottom 1 high. If the box falls, how much kinetic energy will it have when 𝐸k = 𝑚𝑣 2 2 it reaches the ground? 𝐸p = 𝑚𝑔ℎ Independent Practice Complete Potential and Kinetic Energy Calculations Worksheet 2.  CFU 1 Daily Review Which type(s) of energy Kinetic Energy and Gravitational Potential Energy (GPE) are present in each situation below? Give a Kinetic energy (𝐸k ) is the energy possessed by moving reason for your choice. a) A bird in flight. objects. b) A bird sitting in a Objects gain gravitational potential energy (GPE or 𝐸p ) as tree. c) A bowling ball they move away from the Earth’s surface. rolling down a lane.  CFU 1 Daily Review What is the relationship Factors Affecting Kinetic Energy between kinetic energy and an object’s Objects traveling at a higher velocity have more kinetic velocity? energy. CFU 2 Moving objects with a larger mass have more kinetic When moving at the same velocity, which energy. would have more kinetic energy: a car or a truck?  CFU 1 Daily Review What is the relationship Factors Affecting Gravitational Potential Energy between height and the GPE of an object? An object gains more gravitational potential energy as it is CFU 2 raised higher above the Earth’s surface. What is the relationship An object with a larger mass has more GPE than an object between mass and the GPE of an object? with a smaller mass at the same height. CFU 3 Which bird in the photo will have the most GPE? Explain why.  CFU 1 Daily Review When does the watermelon have the Energy Transformation in Falling Objects least GPE? As an object falls, its gravitational potential energy is CFU 2 transformed into kinetic energy. What happens to the The total amount of energy always remains the same – watermelon’s kinetic energy as it falls? energy is never created or destroyed. This is called the law of conservation of energy. CFU 3 At the moment the watermelon is dropped, its GPE is: a) Less than its kinetic energy at the bottom b) Equal to its kinetic energy at the bottom c) More than its kinetic energy at the bottom Justify your answer. Daily Review Describe the kinetic energy and gravitational potential energy (GPE) of the person at each position shown in the diagram. Use the following words: maximum minimum zero increasing decreasing At position A, she has zero kinetic energy and maximum GPE At position B, she has maximum kinetic energy and minimum GPE At position C, she has zero kinetic energy and maximum GPE Daily Review Describe the kinetic energy and gravitational potential energy (GPE) of the object at each position shown in the diagram. Use the following words: maximum minimum zero increasing decreasing At position A, the car has minimum kinetic energy and maximum GPE At position B, the car has increasing kinetic energy and decreasing GPE At position C, the car has maximum kinetic energy and zero GPE At position D, the car has decreasing kinetic energy and increasing GPE Kinetic and Potential Energy Calculations, Pt. 1 Year 10 Physics Learning Objectives We are learning about mechanical energy and how it can be transformed. Success Criteria I can calculate an object’s kinetic energy. I can calculate an object’s gravitational potential energy. CFU What are we going to learn? Activate Prior Knowledge As an object descends, its gravitational potential energy is transformed into kinetic energy. Think, Pair, Share: As they coast down the hill, what happens to the skater’s: velocity? gravitational potential energy? kinetic energy?  CFU 1 Concept Development What unit is used to Measuring Energy measure energy? The amount of energy possessed by an object is measured in joules (J). The unit is named after an English physicist, James Prescott Joule, who studied heat and energy. 1 Joule is the energy needed to move an object 1 metre using 1 newton of force.  CFU 1 Concept Development What is the formula Calculating Kinetic Energy used to calculate kinetic energy? Kinetic energy (𝐸k ) is the energy possessed by moving CFU 2 objects. How much energy does The amount of kinetic energy an object has depends on its a 2 kg object moving at 3 m/s have? mass and velocity. Kinetic energy can be calculated using the formula: 1 𝐸k = 𝑚𝑣 2 2 Where 𝑚 is mass in kg 𝑣 is velocity in m/s  CFU 1 Concept Development What is the formula Calculating Gravitational Potential Energy (GPE) used to calculate gravitational potential Objects gain gravitational potential energy (GPE or 𝐸p ) as energy? they move away from the Earth’s surface. CFU 2 The larger its mass and height, the more energy the object How much gravitational gains. potential energy is gained by a 1 kg object that is lifted 2 m off the GPE can be calculated using the formula: ground? CFU 3 𝐸p = 𝑚𝑔ℎ If the mass of the object doubled, what effect would that have on the gravitational potential Where 𝑚 is mass in kg energy of the object? 𝑔 is gravitational acceleration (9.8 m/s2) ℎ is height in m Concept Development Calculating Gravitational Potential Energy (GPE) The equation for GPE sometimes appears like this: 𝐸p = 𝑚𝑔Δℎ The triangle symbol (Δ) is delta and means “change in” Here it is part of Δℎ, meaning “change in height” Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. A 1 kg book is placed on a shelf 2 m above the ground. What is its gravitational potential energy? 𝑚 = 1 kg 𝐸p = 𝑚𝑔ℎ 𝐸p = 1 × 9.8 × 2 The book has 19.6 J of ℎ=2m 𝐸p = 19.6 gravitational potential 𝑔 = 9.8 m/s2 energy. 𝐸p = ? Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. An object is thrown into the air at a velocity of 10 m/s. If its mass is 2 kg, how much kinetic energy does it have when it leaves the person’s hand? 𝑣 = 10 m/s 1 1 𝐸k = 𝑚𝑣 2 𝐸k = × 2 × 102 The object has 100 J of 2 2 𝑚 = 2 kg 𝐸k = 1 × 100 kinetic energy when it 𝐸k = ? leaves the person’s hand. 𝐸k = 100 Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. What is the kinetic energy of a car with a mass of 2000 kg, when moving with a velocity of 4 m/s? 𝑣 = 4 m/s 1 1 𝐸k = 𝑚𝑣 2 𝐸k = × 2000 × 42 The car’s kinetic 2 2 𝑚 = 2000 kg 𝐸k = 1000 × 16 energy is 16,000 J. 𝐸k = ? 𝐸k = 16,000 Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. A bird is hovering 1 km above the ground. If the bird has a mass of 1 kg, what is its gravitational potential energy? 𝑚 = 1 kg 𝐸p = 𝑚𝑔ℎ 𝐸p = 1 × 9.8 × 1000 The bird’s gravitational ℎ = 1 km = 1000 m 𝐸p = 9800 J potential energy is 9,800 J. 𝑔 = 9.8 m/s2 𝐸p = ? Skill Development / Guided Practice Solving Physics Calculation Problems 1. List the values given in the problem. 2. Choose an equation and rearrange to find the unknown. 3. Substitute values into the equation and solve the equation. 4. Write the final answer with appropriate units and direction. You are standing on the top of a hill. Your gravitational potential energy is 9800 J and you have a mass of 50 kg. What is the height of the hill? 𝑚 = 50 kg 𝐸p = 𝑚𝑔ℎ 9800 ℎ= ℎ=? 50 × 9.8 The hill is 20 m high. 𝑔 = 9.8 m/s2 𝐸p 1000 ℎ= 𝐸p = 9800 J ℎ= 50 𝑚𝑔 ℎ = 20 Relevance Being able to calculate kinetic energy and gravitational potential energy will help you to predict how quickly objects will move as they descend. It will also help you to determine how much energy is converted to heat, sound, and other forms of energy as objects move and collide. Skill Closure Write the equation used to calculate the kinetic energy of an object. Skill Closure Write the equation used to calculate the gravitational potential energy of an object. Reminder: 𝟏 𝑬k = 𝒎𝒗𝟐 Skill Closure 𝟐 𝑬p = 𝒎𝒈𝒉 A box with a mass of 4 kg is placed on a coffee table that is 1 m high. What type of energy does 𝒈 = 𝟗. 𝟖 m/s𝟐 the box have, and why? How much energy does the box have? Independent Practice Complete Potential and Kinetic Energy Calculations Worksheet 1.