AP Multiple Choice
A ball is dropped from rest and falls to the floor. The initial gravitational potential energy of the ball-Earth-floor system is 10 J. The ball then bounces back up to a height where the gravitational potential energy is 7 J. What was the mechanical energy of the ball-Earth-floor system the instant the ball left the floor?
A) 0 J
B) 3 J
C) 7 J
D) 10 J
C) 7J
The amount of energy it had when it left the ground is conserved.
A rock is released from rest from the top of a very high cliff. Approximately how far does the rock travel in the first 7 seconds of its free-fall? (Assume no air friction.)
x = 240.1 meters
x = 1/2 * a* t^2
If you push twice as hard on a stationary brick wall, the amount of work you do:
A) doubles
B) remains constant at zero
C) remains constant with a nonzero value
D) is cut in half
B) remains constant at zero
The wall is not moving.
The equation and units for elastic potential energy are:
Ek = 1/2 * k * x^2
measured in Joules (J)
Who was the 5th President of the U.S.?
James Monroe
A force F is exerted on a 5 kg block to move it across a rough surface. The magnitude of the force is initially 5 N, and the block moves at a constant velocity. While the block is moving, the force is instantaneously increased to 12 N. How much kinetic energy does the block now gain as it moves a distance of 2 m?
10 J
14 J
24 J
34 J
14J
Ke = W = Fd
change in force = 12-5 = 7N
distance = 2m
Complete the stack graphs that is drawn on the board.
*tbd
You throw a ball straight up. Compare the sign of the work done by gravity on the way up and on the way down.
- on the way up and + on the way down
The equation and units for momentum are:
p = m*v
units are kg*m/s
Which two football teams will be playing in Superbowl LIV?
KC Chiefs and SF 49ers
A student is asked to determine the work done on a block of wood when the block is pulled horizontally using an attached string. The student is supplied with a spring scale, a stopwatch, and a meterstick. Which of the following graphical analysis techniques will allow the student to determine the work done on the block by the string?
A) Graphing the force as a function of time and calculating the slope
B) Graphing the force as a function of time and calculating the area under the curve
C) Graphing the force as a function of distance and calculating the slope
D)Graphing the force as a function of distance and calculating the area under the curve
D) Graphing the force as a function of distance and calculating the area under the curve
Remember...you are looking for the units of a N*m!
Draw a force diagram of the following scenario:
A child accelerates down a slide. Friction is present.
Refer to the board
Compared to yesterday, you did 3 times the work in one-third the time. To do so, your power must have been:
A) the same as yesterday's
B) one-third of yesterday's
C) 3 times yesterday's
D) 9 times yesterday's
D) 9 times yesterday's
The equation and units for net force are:
Fnet = m*a
units are Newtons (N)
In which year did RTHS graduate its first class of seniors?
2016
A sled slides down a hill with friction between the sled and hill but negligible air resistance. Which of the following must be correct about the resulting change in energy of the sled-Earth system?
A) The sum of the kinetic energy and the gravitational potential energy changes by an amount equal to the energy dissipated by friction.
B) The gravitational potential energy decreases and the kinetic energy is constant.
C) The decrease in the gravitational potential energy is equal to the increase in kinetic energy.
D) The gravitational potential energy and the kinetic energy must both decrease.
A) The sum of the kinetic energy and the gravitational potential energy changes by an amount equal to the energy dissipated by friction.
A rifle with a mass of 4kg fires a 0.01kg bullet. What is the recoil velocity of the rifle if the bullet is fired at 300m/s?
Conservation of momentum
0 = m1v1 + m2v2
0 = 4v + 0.01(300)
v = -0.75 m/s
A lightweight and a heavy object are sliding with equal speeds along a level frictionless surface. They both slide up the same frictionless hill. Which rises to a greater height?
A) the heavy object because it has greater kinetic energy
B) they both slide to the same height
C) the lightweight object because it weighs less
D) cannot be determined from the given information
B) they both slide to the same height
*Energy is conserved due to no dissipation, so the masses cancel when solving for height.
The equation and units for the range of a projectile fired at an angle are:
X = vcos(theta) * t
units are meters (m)
A) Michael Jackson - "Thriller"
B) Eagles - "Hotel California"
C) Pink Floyd - "The Wall"
D) AC/DC - "Back in Black"
A) Michael Jackson - "Thriller"
An apple is released from rest 500 m above the ground. Due to the combined forces of air resistance and gravity, it has a speed of 40 m s when it reaches the ground. What percentage of the initial mechanical energy of the apple-Earth system was dissipated due to air resistance? Take the potential energy of the apple-Earth system to be zero when the apple reaches the ground.
16%
40%
60%
84%
84%
Calculate the range of a projectile that is fired at 50 m/s at an angle of 15 degrees.
x = 128m
Which of the following statements are TRUE about power?
A) Power is a time based quantity.
B) Power refers to how fast work is done upon an object.
C) Powerful machines simply do a lot of work.
D) The power delivered by a force is the magnitude of the force multiplied by the speed of the object.
E) The Newton*meter is a unit of power.
A, B, D
The equation and units for impulse are:
J = F*t
units are N*s
This was the most popular college major in the year 2017.
Business