1.Easy
A 4 kg rifle, free to move, fires a 4 g bullet at 600 m/s. Both start at rest. Find the recoil speed V of the rifle.
M = 4 kgm = 4 gv = 600 m/s
V = m/s
Momentum & collisions worksheet with answers
2.Easy
A 1000 kg car moving at 10 m/s runs into a stationary 1500 kg car. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).
m1 = 1000 kgv1 = 10 m/sm2 = 1500 kgv2 = 0 m/s
v′ = m/s
3.Medium
A 2.5 kg glider moving at 12 m/s makes a perfectly elastic head-on collision with a 4.5 kg glider at rest on a frictionless track. Find the velocity v′2 of the second glider after the collision.
m1 = 2.5 kgm2 = 4.5 kgv1 = 12 m/sv2 = 0
v′2 = m/s
4.Medium
A 5 g bullet is fired horizontally into a 4 kg wooden block hanging on light strings, and stays inside it. The block swings up until it is 24 cm higher than at the start. Use g = 9.81 m/s². Find the speed v of the bullet before impact.
m = 5 gM = 4 kgh = 24 cmg = 9.81 m/s²
v = m/s
5.Hard
A 0.45 kg ball hits a wall at 22 m/s and bounces straight back at 13 m/s. The contact lasts 40 ms. Find the magnitude of the impulse J the wall gives the ball.
m = 0.45 kgvin = 22 m/svout = 13 m/sΔt = 40 ms
J = N·s
6.Hard
An 8 g bullet is fired horizontally into a 3.5 kg block hanging from light strings 1.1 m long, and stays in it. The strings swing out to a largest angle of 35° from the vertical. Use g = 9.81 m/s². Find the speed v of the bullet before impact.
m = 8 gM = 3.5 kgL = 1.1 mθ = 35°g = 9.81 m/s²
v = m/s
Answer key
- 1. V = 0.6 m/s
- 2. v′ = 4 m/s
- 3. v′2 = 8.571 m/s
- 4. v = 1738 m/s
- 5. J = 15.75 N·s
- 6. v = 866.3 m/s
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