AP Physics C: Mechanics Practice Quiz: Linear Momentum
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Test your understanding with short quizzes. This quiz has 9 questions to check your progress.
Question 1 of 9
All Questions (9)
A) Mass and acceleration
B) Mass and velocity
C) Force and time
D) Mass and displacement
Correct Answer: B
Linear momentum is defined by the equation $\vec{p}=m\vec{v}$, which is the product of an object's mass (m) and its velocity ($\vec{v}$).
A) 50 kg⋅m/s to the right
B) 50 kg⋅m/s to the left
C) 2 kg⋅m/s to the right
D) 0.5 kg⋅m/s to the right
Correct Answer: A
Using the formula $\vec{p}=m\vec{v}$, the momentum is (5 kg) * (10 m/s) = 50 kg⋅m/s. Since momentum is a vector, its direction is the same as the velocity, which is to the right.
A) It has only magnitude and is always positive.
B) It is dependent only on the object's mass.
C) It has both a magnitude and a specific direction.
D) It is a fundamental unit that cannot be broken down.
Correct Answer: C
A vector quantity, by definition, is a physical quantity that has both a magnitude (a numerical value or size) and a direction in space. Linear momentum fits this description.
A) Its momentum remains unchanged.
B) Its momentum's magnitude is halved.
C) Its momentum's direction is reversed.
D) Its momentum becomes zero.
Correct Answer: C
Momentum is a vector quantity with the same direction as velocity ($\vec{p}=m\vec{v}$). If the velocity vector is reversed (e.g., from +v to -v), the momentum vector is also reversed (from +p to -p).
A) East
B) North
C) West
D) It cannot be determined without the object's mass.
Correct Answer: C
The provided content states that momentum is a vector quantity and has the same direction as the velocity. Therefore, if the velocity is directed west, the momentum is also directed west.
A) Object X has twice the momentum of Object Y.
B) Object Y has twice the momentum of Object X.
C) They have the same momentum.
D) Object X has half the momentum of Object Y.
Correct Answer: C
The momentum of Object X is $p_X = (m)(2v) = 2mv$. The momentum of Object Y is $p_Y = (2m)(v) = 2mv$. Their magnitudes are equal.
A) $\vec{p} = m/\vec{v}$
B) $\vec{p} = m\vec{a}$
C) $\vec{p} = m\vec{v}$
D) $\vec{p} = 1/2 m\vec{v}^2$
Correct Answer: C
The provided content explicitly defines linear momentum with the equation $\vec{p}=m\vec{v}$.
A) Both objects have identical momentum vectors.
B) The objects have momentum vectors with the same magnitude but opposite directions.
C) Object 1 has momentum, but Object 2 has zero momentum.
D) Both objects have zero momentum because they will cancel out.
Correct Answer: B
The momentum of Object 1 is $\vec{p_1} = m(+\vec{v})$. The momentum of Object 2 is $\vec{p_2} = m(-\vec{v}) = -m\vec{v}$. The magnitudes are both 'mv', but the directions are opposite, as indicated by the signs.
A) Its velocity has been halved.
B) Its velocity has been doubled.
C) Its velocity has been quadrupled.
D) Its velocity is unchanged.
Correct Answer: B
From the equation $\vec{p}=m\vec{v}$, momentum is directly proportional to velocity. If mass 'm' is constant, then to double the momentum 'p', the velocity 'v' must also be doubled.