1.Easy
A 600 kg car moving at 23 m/s runs into a stationary 1200 kg car. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).
m1 = 600 kgv1 = 23 m/sm2 = 1200 kgv2 = 0 m/s
v′ = m/s
Momentum & collisions worksheet with answers
2.Easy
A 6 kg rifle, free to move, fires a 5 g bullet at 300 m/s. Both start at rest. Find the recoil speed V of the rifle.
M = 6 kgm = 5 gv = 300 m/s
V = m/s
3.Medium
A 4 kg projectile moving horizontally at 33 m/s explodes into two fragments that move along the same line. The 1 kg fragment continues forwards at 65 m/s. Find the velocity v′2 of the 3 kg fragment (positive in the original direction).
M = 4 kgu = 33 m/sm1 = 1 kgv′1 = 65 m/sm2 = 3 kg
v′2 = m/s
4.Medium
A 0.5 kg glider moving at 8 m/s makes a perfectly elastic head-on collision with a 5 kg glider at rest on a frictionless track. Find the velocity v′2 of the second glider after the collision.
m1 = 0.5 kgm2 = 5 kgv1 = 8 m/sv2 = 0
v′2 = m/s
5.Hard
A 0.2 kg ball hits a wall at 29 m/s and bounces straight back at 20 m/s. The contact lasts 40 ms. Find the magnitude of the impulse J the wall gives the ball.
m = 0.2 kgvin = 29 m/svout = 20 m/sΔt = 40 ms
J = N·s
6.Hard
A 0.2 kg ball hits a wall at 21 m/s and bounces straight back at 7 m/s. The contact lasts 5 ms. Find the average force Favg of the wall on the ball.
m = 0.2 kgvin = 21 m/svout = 7 m/sΔt = 5 ms
Favg = N
Answer key
- 1. v′ = 7.667 m/s
- 2. V = 0.25 m/s
- 3. v′2 = 22.33 m/s
- 4. v′2 = 1.455 m/s
- 5. J = 9.8 N·s
- 6. Favg = 1120 N
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