Honors Physics 1 Unit 3 Notes: Momentum PDF

Honors Physics 1 Notes Unit 3: Momentum Honors Physics 1 Name _______________________________ Hour _____ Unit 3 Preferred mode of transportation: _________...

Honors Physics 1 Notes Unit 3: Momentum Honors Physics 1 Name _______________________________ Hour _____ Unit 3 Preferred mode of transportation: __________________ Notes Unit 3: How are Forces Linked to Momentum? 3.1: Identify and describe the momentum of each object in a system both conceptually and mathematically. 1. Definition of Momentum: a. *Momentum measures b. Equation: Units: c. Mass and velocity are both _________________ related to momentum. d. Because velocity is a _____________, momentum is also a vector--direction matters. e. Practice: i. Suppose Henry (51 kg) is running at 2.0 m/s. What is his momentum? How will his momentum change if he doubles his speed? ii. What is the mass of a tortoise if he has 0.14 kg-m/s of momentum when moving at 0.0002 m/s? iii. Calculate the momentum of each object separately and then find their total momentum together. iv. Calculate the momentum of each object separately and then find their total momentum together. 1  Honors Physics 1 Notes Unit 3: Momentum 2. Changing Momentum: a. For momentum to change either an object’s ________________ or ________________ (or both) must change. We will deal only with changing ______________. b. If an object speeds up its momentum _________________ and if an object slows down its momentum _______________. c. We know that ______________ causes acceleration. If an object experiences a net force i. in the same direction it is moving, its momentum will _______________. ii. in the opposite direction it is moving, its momentum will _______________. d. Practice: i. Suppose a car (2700 kg) driving at 12 m/s comes to rest upon hitting a cement barrier. What is the car’s change in momentum? ii. Calculate the change in momentum of a tennis ball (0.05 kg) which is moving to the right, hits a wall, and bounces back as illustrated in the picture. 3.2: Synthesize the concepts of force and change in momentum. 3. Impulse and Momentum: a. Recall Newton’s 2nd Law: ________________ b. When Newton originally studied what we now call Newton’s 2nd Law he actually wrote it this way: This is known as the Impulse-Momentum Equation. 4. Definition of Impulse a. Impulse is a ________________ acting for a certain amount of ______________. b. Impulse causes momentum to __________________. c. Equation: Units: 2  Honors Physics 1 Notes Unit 3: Momentum d. Practice: i. Calculate the impulse experienced by a snowball that is thrown with a force of 28 N and in contact with the thrower’s hand for 0.65 seconds. ii. How would the impulse of the snowball in the previous question change if the throwing force acted for twice as long? 5. Applications/Practice of the Impulse-Momentum Equation: a. Bungee Jumping b. Egg Toss c. Suppose Hilda is holding her umbrella during a rainstorm when the raindrops turn to hail. Although the number of “drops” (and their mass) hitting the umbrella remains the same, why does it become more difficult to hold the umbrella? d. A tennis ball (0.059 kg) is initially moving to the right at 35 m/s when it is hit by a racquet and sent flying to the left at 42 m/s. If the racquet delivers a force of magnitude 55 N, how long were the racquet and ball in contact? 3  Honors Physics 1 Notes Unit 3: Momentum e. The diagram below depicts the before and after collision speeds of a car that undergoes a head-on collision with a wall. In Case A the car does not have a crumple zone and it bounces off of the wall. In Case B the car crumples and sticks to the wall. i. In which case is the change in momentum the greatest? ii. In which case is the impulse the greatest? iii. In which case is the force that acts upon the car the greatest (assuming the contact time is equal for both A and B)? i. Suppose the car in Case A is in contact with the wall for 0.20 seconds. Calculate the force experiences by the 2300 kg car. 3.3: Analyze data to draw conclusions about the momentum of a system of objects. Refer to your Conservation of Momentum Lab for data analysis related to the momentum of a system. 3.4 Apply the model of momentum conservation to systems of objects both conceptually and mathematically. 6. Review of Newton’s 3rd Law and the Impulse-Momentum Equation: a. Suppose the 7-ball is moving to the right and strikes the 8-ball which was initially at rest. i. From Newton’s 3rd Law we know that when the pool balls collide, the 7-ball will apply a force on the 8-ball and the 8-ball will apply a force on the 7-ball that is _________________ in size but ________________ in direction. ii. Each pool ball experiences the same magnitude of force for the same amount of time which means each ball experiences the same amount of ________________. iii. We know that impulse causes _________________ to change. If each ball experiences an impulse equal in magnitude then they must also experience ______________ changes in momentum. 4  Honors Physics 1 Notes Unit 3: Momentum iv. This means that in the collision, the momentum lost by the 7-ball will be equal to the momentum gained by the 8-ball and the total momentum of the system will stay _____________ during the collision, even though the momentum of individual objects does change. v. In summary, force pairs that occur during collisions are called internal forces and ______ _________ change the momentum of the system. 7. Law of Conservation of Momentum: b. In words: If no external (or net) force acts on a system of objects the _________________ of the system is ____________________. c. In equation form: d. Applications/Practice: * Hints for solving: 1. Draw a Picture. 2. Label the Objects. 3. Are the objects together or separate after the collision? 4. Write the Original Equation & Show Your Work! ii. Suppose a blob of clay moving at 12 m/s collides with an identical blob of clay that was initially at rest. The two stick together. What is the velocity of the combined blobs after the collision? iii. Two skaters are stationary until they push off from each other. What is the total momentum of the system beforehand? What is the momentum of the system after they push off? 5  Honors Physics 1 Notes Unit 3: Momentum iv. A 12 kg cat moving at 15 m/s jumps onto a 5 kg skateboard which was initially at rest. How fast do the cat and skateboard move together? v. Lloyd rolls a 7.0 kg bowling ball down the alley for the league championship. One pin is still standing and Lloyd hits it head on with a velocity of 9.0 m/s. The 2.0 kg pin acquires a forward velocity of 14.0 m/s. What is the ball’s new velocity? vi. A 2500 kg car is traveling east at 18 m/s and collides head on with a 3200 kg truck traveling west at 22 m/s. The vehicles become entangled and move together after the collision. With what speed do they move? vii. A 1000 kg cannon fires a 10 kg cannonball. If the cannonball travels at 50 m/s once fired, what is the recoil speed of the cannon? 6