Download AP Physics 1 Quiz: Conservation of Energy Formulas

AP Physics 1 Quiz: Conservation of Energy
Formulas:
W=FdCosΘ
KE=½mv2
PEg=mgh
PEe=½kx2
g=9.81 m/s2
1) A cart with a mass of 2.0 kg is on frictionless ramp so that its gravitational potential energy is 10
Joules. If the cart is released from rest, what is its velocity at the bottom of the ramp?
a. Can’t be answered without knowing the angle of the ramp
b. About 3.2 m/s
c. About 20 m/s
d. About 10 m/s
2) When the cart if halfway down the ramp, its gravitational potential energy will be…
a. Can’t be answered without knowing the angle of the ramp
b. More than 5 Joules
c. Less than 5 Joules
d. 5 Joules
3) When the cart is halfway down the ramp, its speed is…
a. Half its speed at the bottom
b. Greater than half its speed at the bottom
c. Less than half its speed at the bottom
d. The same as its speed at the bottom
4) Imagine on the ramp there is a small, but measureable amount of friction. Due to the friction,
which statement below would most likely be true?
a. The cart’s time to the bottom of the ramp will be shorter
b. The cart’s kinetic energy at the bottom will be less than its potential energy at the top
c. The cart’s kinetic energy at the bottom will be greater than its potential energy at the top
d. The cart’s velocity at the bottom of the ramp will be greater
5) A 200 gram rock is placed on a spring that has been compressed 10 cm vertically. The elastic
potential energy of the compressed spring is 10 Joules. When the spring is released, what is the
kinetic energy of the rock the moment it leaves the spring?
a. 10 Joules
b. 2 Joules
c. 1 Joule
d. 0.2 Joules
6) When the stone is launched upward, it will reach a certain height, d, before it falls back down.
How can we calculate d?
a. mgh = Initial kinetic energy; m=0.2 kg, g=9.81; solve for h
b. ½kx2 = Elastic potential energy; k=10 J; solve for x
c. ½kx2 = Elastic potential energy; x = ½ at2 ; a=9.81; solve for t
d. ½mv2 = Kinetic energy; m=0.2kg, KE = 10 J; solve for v
7) What adjustment of the spring/rock system would allow the rock to reach a height of 2d?
a. Compress the spring twice the distance as before
b. Use a rock twice as heavy as before
c. Changes ‘a’ and ‘d’ will both allow the rock to reach a height of 2d
d. Use a spring with twice the spring constant as before
8) Which explanation correctly describes the transfers and transformations of mechanical energy
that limit the rock to reaching height d?
a. Because of conservation of energy, Elastic PE is taken out of the spring, the rock then
creates KE that increases until it reaches height d
b. All of the rock’s KE is transformed into friction, causing it to stop at height d
c. Because of conservation of energy, Elastic PE is transferred from the spring to the rock
where it’s transformed to KE, then to Gravitational PE
d. Because of conservation of energy, the minimum amount of energy the rock can have is
transformed into gravity while all other forms of energy disappear at height h
9) Student A and student B are the same mass. They are both at the bottom of a 10 m tall hill.
Student A takes a slow, gradual path and reaches the top in 3 minutes. Student B takes a quick,
steep path and reaches the top in 1 minute. Which of the following statements is FALSE about
this scenario?
a. Students A and B did the same amount of work
b. Student A did 3 times as much work as Student B
c. Student B did work 3 times as fast as student A
d. If you include the work done by gravity, the net work done on each student is zero
10) Two identical blocks, A and B are sliding along sliding along a frictionless, level table at velocity
v when they each encounter a rough surface such that each has the same coefficient of friction, μ,
with the blocks. Block A encounters the rough surface for 10 cm, yet is still moving at vA, and
Block B encounters the rough surface for 20 cm, yet is still moving at vB. Which prediction is
most likely to reflect the data and the physics of the experiment?
a. The velocities vA and vB will be the same because the force of friction on each block is
the same
b. The velocity vA will be greater than vB because a greater force of friction will act on
block B than will act on block A
c. The velocity vA will be greater than vB because the equal force of friction will act on
block B for more time than it act on block A
d. Because of conservation of energy, each block will have the same amount of mechanical
energy at the end of the experiment.