PHYS 141 Exam 2 Concept EXAM QUESTIONS AND
CORRECT ANSWERS LATEST UPDATE 2025-2026
The mass of the moon is 1/81 of the mass of the earth. Compared to the gravitational
force that the earth exerts on the moon, the gravitational force that the moon exerts on
the earth is - answer>>>equally strong.
Compared to the earth, a distant planet has twice the mass and twice the radius. This
means that compared to the earth's surface gravity, the surface gravity on the other
planet is - answer>>>half as much.
A box is sitting in the back of the truck. The truck begins to accelerate forward (to the
right) and the box does not slip. In a free-body diagram for the box, the force of friction
on the box points - answer>>>to the right.
Consider the recoil of a rifle when it is fired. Recoil is an example of which of the
following concepts?
a) Newton's Third Law of Motion
b) Impulse
c) Conservation of Momentum
d) all of the above
e) none of the above - answer>>>d
A net force of 200 N acts on a 100-kg boulder, and a force of the same magnitude acts
on a 130-g pebble. How does the rate of change of the boulder's momentum compare
to the rate of change of the pebble's momentum? - answer>>>equal to
A uranium nucleus is at rest and undergoes a fission reaction, splitting into two
fragments, one heavy and the other light. The magnitude of momentum is greater for
which fragment? - answer>>>They both have the same momentum.
, On a frictionless surface, a sliding box collides and sticks to an identical box initially at
rest. What is the final kinetic energy of the system in terms of the initial KE? -
answer>>>KEf = 1/2KEi
A rock is thrown straight up from the surface of the earth. Ignoring air resistance, which
of the following statements is correct as the rock moves upward?
a) total energy of the rock increases
b) both the kinetic energy and the GPE of the rock remain the same
c) both the GPE and the total energy of the rock increase
d) both the kinetic energy and the total energy of the rock decrease
e) the kinetic energy of the rock decreases and the GPE of the rock increases -
answer>>>e
A stationary bomb explodes in space breaking into several fragments. The net external
force on the bomb at the time of the explosion is zero. Which statement is correct?
a) the total kinetic energy is conserved
b) the sum of the kinetic energies of all the fragments is zero
c) the vector sum of the linear momenta of the fragments is zero
d) the velocity of any one fragment must be equal to the velocity of any other fragment
e) the speed of any one fragment must be equal to the speed of any other fragment -
answer>>>c
Complete the statement: A collision is elastic if
a) the total final momentum of the system is zero
b) the objects stick together
c) the final kinetic energy of the system is zero
d) the total kinetic energy of the system is conserved
e) the total momentum of the system is conserved - answer>>>d
CORRECT ANSWERS LATEST UPDATE 2025-2026
The mass of the moon is 1/81 of the mass of the earth. Compared to the gravitational
force that the earth exerts on the moon, the gravitational force that the moon exerts on
the earth is - answer>>>equally strong.
Compared to the earth, a distant planet has twice the mass and twice the radius. This
means that compared to the earth's surface gravity, the surface gravity on the other
planet is - answer>>>half as much.
A box is sitting in the back of the truck. The truck begins to accelerate forward (to the
right) and the box does not slip. In a free-body diagram for the box, the force of friction
on the box points - answer>>>to the right.
Consider the recoil of a rifle when it is fired. Recoil is an example of which of the
following concepts?
a) Newton's Third Law of Motion
b) Impulse
c) Conservation of Momentum
d) all of the above
e) none of the above - answer>>>d
A net force of 200 N acts on a 100-kg boulder, and a force of the same magnitude acts
on a 130-g pebble. How does the rate of change of the boulder's momentum compare
to the rate of change of the pebble's momentum? - answer>>>equal to
A uranium nucleus is at rest and undergoes a fission reaction, splitting into two
fragments, one heavy and the other light. The magnitude of momentum is greater for
which fragment? - answer>>>They both have the same momentum.
, On a frictionless surface, a sliding box collides and sticks to an identical box initially at
rest. What is the final kinetic energy of the system in terms of the initial KE? -
answer>>>KEf = 1/2KEi
A rock is thrown straight up from the surface of the earth. Ignoring air resistance, which
of the following statements is correct as the rock moves upward?
a) total energy of the rock increases
b) both the kinetic energy and the GPE of the rock remain the same
c) both the GPE and the total energy of the rock increase
d) both the kinetic energy and the total energy of the rock decrease
e) the kinetic energy of the rock decreases and the GPE of the rock increases -
answer>>>e
A stationary bomb explodes in space breaking into several fragments. The net external
force on the bomb at the time of the explosion is zero. Which statement is correct?
a) the total kinetic energy is conserved
b) the sum of the kinetic energies of all the fragments is zero
c) the vector sum of the linear momenta of the fragments is zero
d) the velocity of any one fragment must be equal to the velocity of any other fragment
e) the speed of any one fragment must be equal to the speed of any other fragment -
answer>>>c
Complete the statement: A collision is elastic if
a) the total final momentum of the system is zero
b) the objects stick together
c) the final kinetic energy of the system is zero
d) the total kinetic energy of the system is conserved
e) the total momentum of the system is conserved - answer>>>d
