AP Physics 1 Unit 4 Practice Test

Pick a unit and take a timed, AP^®-style test built only from that unit's questions — with AI feedback on every free-response answer.

unit 1 unit 2 unit 3 unit 4 unit 5 unit 6 unit 7 unit 8

Linear Momentum

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Two ways to practice unit 4

standard

The exam experience, sized to one unit — timed like the real thing

20 Multiple Choice Questions

40 min

1 FRQ – FRQ 1 – Mathematical Routines

24 min

1 FRQ – FRQ 2 – Translation Between Representations

24 min

Sections run back-to-back with the same directions, timers, and scoring as the real exam

Total: 1 hr 28 min

customizable

Pick your own mix of question types

multiple choice questions

free response questions (choose as many as you want)

FRQ 1 – Mathematical Routines · 24 minFRQ 2 – Translation Between Representations · 24 minFRQ 3 – Experimental Design · 24 minFRQ 4 – Qualitative/Quantitative Translation · 24 min

Total: 40 min

How scoring works: multiple choice is scored instantly, free-response answers get point-by-point AI feedback, and your result is a percentage for this unit — not a projected AP^® score.

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AP Physics 1 Unit 4 practice questions

Try 10 multiple-choice questions from Unit 4 here. Pick an answer to see why it's right or wrong, then take the timed test above for a full AP-style set.

Question 1
A 0.40 kg ball falls vertically and hits the floor with a speed of 5.0 m/s, rebounding upward with a speed of 3.0 m/s. If the ball is defined as the system, what is the magnitude of the change in momentum of the system during the collision?
0.80 kg·m/s
2.0 kg·m/s
3.2 kg·m/s
8.0 kg·m/s
Show answer
Answer: (C)
Calculates the change in velocity as final minus initial ( $3 - (-5) = 8$ m/s) and multiplies by mass ( $0.40 \times 8$ ).
Question 2
Cart A (2.0 kg) moving right at 3.0 m/s collides with Cart B (1.0 kg) moving left at 2.0 m/s. If the system consists of both carts and friction is negligible, what is the magnitude of the total momentum of the system after the collision?
1.0 kg·m/s
4.0 kg·m/s
6.0 kg·m/s
8.0 kg·m/s
Show answer
Answer: (B)
Sums the initial momenta vectors ( $2(3) + 1(-2) = 4$ ) and recognizes that total momentum is conserved for the two-cart system.
Question 3
A 5.0 kg box slides across a horizontal surface with an initial speed of 4.0 m/s. A constant friction force of 10 N acts on the box opposite to its motion. If the box is the system, what is the magnitude of its momentum 1.5 seconds later?
5.0 kg·m/s
15 kg·m/s
20 kg·m/s
35 kg·m/s
Show answer
Answer: (A)
Calculates initial momentum ( $20$ ), subtracts the impulse from friction ( $10 \times 1.5 = 15$ ), resulting in $5$ .
Question 4
A 3.0 kg object moves north at 4.0 m/s, and a 2.0 kg object moves south at 6.0 m/s. What is the magnitude of the velocity of the center of mass of the two-object system?
0 m/s
2.4 m/s
4.8 m/s
5.0 m/s
Show answer
Answer: (A)
Calculates total momentum ( $12 - 12 = 0$ ), which implies the center of mass velocity is zero.
Question 5
A cannon of mass 500 kg fires a projectile of mass 10 kg horizontally at a speed of 200 m/s. If the cannon and projectile are defined as the system and friction is negligible, what is the recoil speed of the cannon?
0.25 m/s
4.0 m/s
20 m/s
40 m/s
Show answer
Answer: (B)
Sets initial momentum to zero and equates the magnitude of cannon and projectile momenta ( $500v = 10 \times 200$ ).
Question 6
A 2.0 kg rock is thrown vertically upward. Consider the rock alone as the system. Between the time it is thrown and the time it reaches its peak 1.5 seconds later, what is the magnitude of the change in the system's momentum? (Use $g = 10 \text{ m/s}^2$ )
15 kg·m/s
20 kg·m/s
30 kg·m/s
45 kg·m/s
Show answer
Answer: (C)
Calculates the impulse provided by the external force of gravity ( $J = F_{ext}t = mgt = 2 \times 10 \times 1.5$ ).
Question 7
A net force acting on a 4.0 kg object varies with time. The force is constant at 12 N for 3.0 s, then drops instantly to zero. If the object starts from rest, what is its final speed?
3.0 m/s
9.0 m/s
12 m/s
36 m/s
Show answer
Answer: (B)
Calculates impulse ( $12 \times 3 = 36$ ) and divides by mass ( $36 / 4$ ) to find the change in velocity.
Question 8
Two ice skaters, mass 60 kg and 40 kg, stand together at rest on frictionless ice. They push off each other, and the 40 kg skater moves right at 3.0 m/s. If the system is defined as the 60 kg skater only, what is the magnitude of the impulse exerted on this system?
80 N·s
120 N·s
180 N·s
200 N·s
Show answer
Answer: (B)
Calculates the momentum of the other skater ( $40 \times 3 = 120$ ) and applies Newton's 3rd Law.
Question 9
A 1000 kg car traveling at 20 m/s collides with a stationary 1500 kg truck. They lock bumpers and move together. Calculating the final velocity requires defining the system as both vehicles to conserve momentum. What is this final speed?
8.0 m/s
12 m/s
13 m/s
20 m/s
Show answer
Answer: (A)
Equates initial momentum ( $20,000$ ) to final momentum ( $2500v$ ) and solves for $v$ .
Question 10
A 20 kg cart moves horizontally at 4.0 m/s. A 5.0 kg sandbag is dropped vertically into the cart. If the system is the cart and sandbag, horizontal momentum is conserved. What is the final speed?
3.2 m/s
4.0 m/s
5.0 m/s
16 m/s
Show answer
Answer: (A)
Conserves horizontal momentum: $20(4) = (20+5)v$ , so $80 = 25v$ .

What's on the AP Physics 1 Unit 4 practice test

The standard version takes about 88 minutes and follows the timing and directions of the AP exam, sized to one unit:

20 Multiple Choice Questions (40 minutes)
1 FRQ – FRQ 1 – Mathematical Routines (24 minutes)
1 FRQ – FRQ 2 – Translation Between Representations (24 minutes)

Questions are drawn from 794 multiple-choice questions and 42 FRQs written for Unit 4, Linear Momentum.

Practice AP Physics 1 Unit 4 FRQs

Answer the unit's free-response questions one at a time and get a score on every part.

FRQ 1 – Mathematical Routines (5 questions)
FRQ 2 – Translation Between Representations (9 questions)
FRQ 3 – Experimental Design (9 questions)
FRQ 4 – Qualitative/Quantitative Translation (19 questions)

AP Physics 1 Unit 4 Practice Test

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AP Physics 1 Unit 4 practice questions

What's on the AP Physics 1 Unit 4 practice test

Practice AP Physics 1 Unit 4 FRQs

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