Honors Physics Midterm Outline PDF

Honors Physics Midterm Outline The following document contains the main topics that will be on your midterm. This should not be the only resource you use to prepare for your midterm. Don’t forget to review your old exams, labs, homework assignments, and the Midterm moodle quiz. I. Motion in One Dim...

Honors Physics Midterm Outline The following document contains the main topics that will be on your midterm. This should not be the only resource you use to prepare for your midterm. Don’t forget to review your old exams, labs, homework assignments, and the Midterm moodle quiz. I. Motion in One Dimension - 1d Kinematics from the Physics Classroom, and Unit 1 and 2 on Moodle a.​ Variables: Position (a vector) (units: meters), time (a scalar) (units: seconds) b.​ Distance (d) ​ The total path that an object travels. c.​ Displacement (∆x) ​ How far an object is from where it started. ​ ∆x = xf - xi ​ Displacement includes the direction which makes it a vector quantity d.​ Speed (S) ​ The distance that an object travels per unit of time. How fast or slow an object is traveling. 𝑑 ​ Formula: 𝑆𝑎𝑣𝑒𝑟𝑎𝑔𝑒 = ∆𝑡 ​ SI Unit: m/s ​ Speed does not have a direction associated with it. Speed is a scalar quantity. e.​ Average Velocity ​ The speed and direction of an object. ∆𝑥 ​ Formula: 𝑣𝑎𝑣𝑒𝑟𝑎𝑔𝑒 = ∆𝑡 ​ Unit: m/s ​ Vector f.​ Average Acceleration ​ Change in velocity per unit of time. ∆𝑣 ​ 𝑎𝑎𝑣𝑒𝑟𝑎𝑔𝑒 = ∆𝑡 ​ Unit: m/s2 ​ Vector g.​ Instantaneous vs. Average Velocity – Average velocity is displacement divided by the elapsed time. Instantaneous velocity is the velocity of the object at a specific moment in time. The initial or final velocity is an instantaneous velocity. ​ Formula: vf = vi + a∆t​ h.​ Position vs. Time Graph ​ Position of the object can be found at any moment in time. ​ The slope is the average velocity. ​ Linear (straight) represents a constant velocity.  i.​ Velocity vs. Time Graph ​ Velocity can be found at any moment in time. ​ Horizontal shape represents a constant velocity. ​ The slope is the average acceleration. j.​ Acceleration vs. Time Graph ​ The acceleration of the object can be found at any moment of time. k.​ Kinematic Equation: ​ A formula that can be used to find how far an object travels if the object is accelerating is: ∆x = vi∆t + ½ a∆t2 ​ A formula that can be used to solve for vf, vi, ∆x, or a if the time is not provided is: vf2 = vi2 + 2a∆x l.​ You should know how to draw graphs of position, velocity, and acceleration vs. time given position and time data. You should know how to interpret position, velocity, and acceleration vs. time graphs. You should be able to find position, velocity, acceleration, and time, given the other variables. You should know the difference between average and instantaneous velocity. You should be able to find position, velocity and acceleration from motion graphs. You should be able to solve free-fall problems. II. Newton’s Laws of Motion- Newton’s Laws from the Physics Classroom. Unit 2 on Moodle a.​ Newton’s First Law: A body at rest will stay at rest, and a body in motion will stay in motion unless acted on by an outside force. a.​ Inertia is the property of an object to resist a change in motion. The more mass an object has, the more inertia it has. b.​ Newton’s Second Law: Acceleration is directly proportional to the net force, and inversely proportional to the mass of the accelerated body. Fnet = ma c.​ Newton’s Third Law: Every time a force acts on a body, the body acts with an equal and opposite force on whatever is applying the force. d.​ When a force is applied to an object and it doesn’t move, static friction is acting on the object. When two surfaces slide past each other, kinetic friction is acting on the object. The maximum static friction is greater than kinetic friction. e.​ The equation for friction is Ff,s ≤µsFN. µ is the coefficient of friction. The coefficient is constant between two surfaces and does not have units. f.​ Free Body Diagrams are illustrations showing the forces acting on an object. The forces originate from the center of mass (dot). Each arrow is labeled (Fg, FN, FA, Ff , etc.) The length of the force vectors represent the size of the force. g.​ The unit for force is a Newton or kg m/s2  h.​ 4-step program to solve any force problem a.​ Draw a free body diagram b.​ Write a net force equation for the X and Y direction. c.​ Sub in any formulas such as (Fg = mg, FNET = ma….) d.​ Solve for the missing variable i.​ Equilibrium is when the net force on the object is 0 N. An object travels at a constant velocity (acceleration is 0 m/s2) when the object is in equilibrium. You should be able to calculate the weight (mg, the force of gravity) given the body’s mass. You should be able to calculate the acceleration, mass or force on an object. You should be able to decompose a force vector into its components parallel and normal to a surface. You should be able to draw a free-body diagram and use it to calculate the net force on an object. Lastly, to find the weight of an object the equation is Fg =mg (this equation is not on the equation sheet). III. Motion in Two Dimensions - Projectiles and 2d motion and Free Fall from the Physics classroom. Unit 3 on Moodle. a.​ The acceleration due to gravity on Earth is approximately -10 m/s2. All objects fall at the same rate in the absence of friction b.​ Acceleration is 0 m/s2 in the x direction (constant velocity) and it is -10 m/s2 in the y direction. c.​ Time is the same on the x and y-axis. d.​ The velocity is 0 m/s in the y-direction at the maximum height of a vertically launched projectile. e.​ Understand the characteristics of the position vs. time graph and velocity vs. time graph for the x, and y axis for a projectile. You should be able to solve for the hang time, height and range using the information on the x and y axis for a free fall or 2d launched problem. IV. Law of Universal Gravitation - Law of Universal Gravitation from the Physics classroom website. Unit 3 on Moodle 𝑚1𝑚2 a.​ The formula is :𝐹𝑔 = 𝐺 2 𝑑 b.​ There is a gravitational force of attraction between any two masses. c.​ As the distance increases between two bodies the gravitational force of attraction decreases by the inverse square law (Butter Gun). d.​ The relationship between mass and gravitational force is directly proportional.  You should be able to calculate the gravitational force between two masses. You should be able to explain how the gravitational force changes as the masses and distance changes. You should be able to explain how the gravitational force affects orbits and how all masses attract each other. V. Energy, Work and Power- Energy, Work and Power from the Physics classroom. Unit 4 on Moodle. a.​ Mechanical Energy i.​ Potential (Gravitational and Elastic Potential) and Kinetic energy are types of mechanical energy. ii.​ ME = PE + KE or ME = PEg + PEs + KE iii.​ Energy is a Scalar​ b.​ Gravitational Potential Energy i.​ Formula : ∆PEg = mg∆h ii.​ Unit: Joule (J) iii.​ g ≈ 10 N/kg iv.​ m = mass in kg v.​ ∆h is the height from a reference height. vi.​ Gravitational Potential energy is based on how far the object is from a reference height in a gravitational field. c.​ Elastic Potential energy i.​ Formula: PEs = ½ kx2 ii.​ Unit: Joule (J) iii.​ k is the spring constant and it is measured in N/m. iv.​ x is the distance the spring is stretched in meters. v.​ If an elastic is displaced (stretched or compressed) from an equilibrium position, it has elastic potential energy. d.​ Kinetic Energy i.​ Formula KE = ½ mv2 ii.​ Unit: Joule (J) iii.​ m = mass in kg iv.​ v is the speed in m/s v.​ Kinetic Energy is energy in motion e.​ Work - the amount of energy that is added or taken away from a system. i.​ W = ∆E j.​ W = F d - the force needs to be parallel to the magnitude of the displacement of the object. k.​ Unit: Joule (J) l.​ Work is a scalar quantity. m.​ Positive work is when mechanical energy is added to the system and negative work is when mechanical energy is taken away from the system. n.​ The total energy of a system is always conserved. Some of the energy could be transformed into heat, light, sound……  f. Power i.​ The rate at which work is done is the power of the object. ii.​ Equation: P = W/∆t iii.​ Unit: Watt (W) or J/s iv.​ Power is a scalar quantity Mechanical Energy Conservation a.​ If external forces are not acting on the system (friction), the total mechanical energy is the same throughout the entire system. b.​ MEi = MEf You should be able to calculate the gravitational potential energy, elastic potential energy and kinetic energy in a system. You should be able to explain how energy transforms from one form to another but the total energy of the system remains the same. Work is when the mechanical energy of a system is added or taken away. You should be able to solve for the work on a system using W = ∆ME (this equation is not on the equation sheet) and W= F d. Lastly, you should be able to calculate the power of an object. VI: Momentum and Impulse - Momentum Conservation and Impulse from the physics classroom website. Unit 5 on Moodle. A.​ Momentum is the product of an object’s mass and velocity: p = mv ○​ The unit is kg m/s ○​ Vector quantity B.​ Total Momentum is conserved in the absence of external forces. C.​ To solve momentum conservation problems, find the total momentum before or after the collision. You may need to find the individual momentums and add them together. The key is that the total momentum before the collision equals the total momentum after the collision. D.​ Types of Collisions: Elastic Collision -​ Two objects bounce off each other. -​ Only in truly elastic collisions is the mechanical energy conserved. Inelastic Collision -​ Two objects stick together. -​ Mechanical energy is not conserved. Explosions -​ One object separates from another object. E.​ Impulse ○​ Impulse is the change in momentum of an object.  ○​ To change the momentum of an object a force must be applied for a specific time interval. ○​ Formula: ∆p = F∆t ○​ Unit is kg m/s or N s ○​ If you are able to increase the time interval to change the momentum of an object the force must be decreased. This is important with lots of safety devices (air bags, helmets, egg drop device) You should be able to calculate the momentum of an object. You should also be able to apply the principle of momentum conservation to solve for the total momentum and individual momentums in a system. This can also be used to solve for the velocity of an object. Lastly, you should be able to solve for the impulse and explain how the force and time of an object changes during a collision.  Honors Physics Toolbox: 1st Semester Equations 𝑣𝑎𝑣𝑒𝑟𝑎𝑔𝑒 = ∆𝑥 ∆𝑡 ​ ​ ​ 𝑆𝑎𝑣𝑒𝑟𝑎𝑔𝑒 = 𝑑 ∆𝑡 ​​ ​ ​ 𝑎𝑎𝑣𝑒𝑟𝑎𝑔𝑒 = ∆𝑣 ∆𝑡 ​ ​ ​ ​ ​ ​ vf = vi + a∆t​ ​ ​ Δx = vi Δt + ½ aΔt2 ​ ​ ​ ​ vf2 = vi2+2aΔx ​ ​ FNET = ma​ ​ ​ ​ Ff = µFN​ ​ ​ ​ Fg = mg​ 𝑚1𝑚2 𝐹𝑔 = 𝐺 2 ​​ ​ ∆PEg = mg∆h​ ​ ​ ​ KE = ½ mv2​ 𝑑 PEs = ½ kx2​ ​ ​ ​ |𝐹| = 𝑘|𝑥|​ ​ ​ ​ W =∆E= F d​ 𝑊 𝑃= ∆𝑡 ​ ​ ​ ​ p = mv​ ​ ​ ​ F ∆t = ∆p​ 𝐸𝑜𝑢𝑡 𝑒𝑓𝑓 = 𝐸𝑖𝑛 ​ Variables: a = acceleration ​ ​ ​ ​ ​ ​ Fnet = net force v = velocity​ ​ ​ ​ ​ ​ ​ Ff = force of friction ∆x = change in position​​ ​ ​ ​ ​ µ = coefficient of friction ∆t = change in time​ ​ ​ ​ ​ ​ FN = normal force PEg = gravitational potential energy​ ​ ​ ​ k = spring constant PEs = spring Potential energy​ ​ ​ ​ ​ Fs = force on a spring m = mass​ ​ ​ ​ ​ ​ ​ h = height​ ​ ​ ​ E = Energy​ ​ ​ ​ ​ ​ ​ d = distance W = work​ ​ ​ ​ ​ ​ ​ p = momentum KE = kinetic energy​ ​ ​ ​ ​ ​ eff = efficiency​ P = Power​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Constants: g ≈ 10 N/kg G = Gravitational Constant = 6.7 x 10-11 Nm2/kg2 acceleration due to gravity ≈ - 10 m/s2 Conversions: 1 mile = 1600 m ​ ​ ​ ​ 1 hr = 3600 s Mathematics​ 2 −𝑏± 𝑏 −4𝑎𝑐 Quadratic Formula: ax2+bx+c=0 ​ then 𝑥 = 2𝑎 Pythagorean Theorem: a2 + b2 = c2 “May the force be with you” Image is from: http://i1.wp.com/spiritual-artwork.org/wp-content/uploads/2015/05/178.-Yoda-The-Grand-Master-Star-Wars-May-The-Force-Be-With -You-1024x576.jpg?resize=350%2C200