1.Easy
A 3 kg rifle, free to move, fires a 5 g bullet at 700 m/s. Both start at rest. Find the recoil speed V of the rifle.
M = 3 kgm = 5 gv = 700 m/s
V = m/s
Momentum & collisions worksheet with answers
2.Easy
A 600 kg car moving at 6 m/s runs into a stationary 1700 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 = 6 m/sm2 = 1700 kgv2 = 0 m/s
v′ = m/s
3.Medium
A 0.5 kg glider moving at 2 m/s makes a perfectly elastic head-on collision with a 2.5 kg glider at rest on a frictionless track. Find the velocity v′2 of the second glider after the collision.
m1 = 0.5 kgm2 = 2.5 kgv1 = 2 m/sv2 = 0
v′2 = m/s
4.Medium
A 3.5 kg glider moving at 4 m/s makes a perfectly elastic head-on collision with a 2 kg glider at rest on a frictionless track. Find the velocity v′1 of the first glider after the collision (positive in its original direction).
m1 = 3.5 kgm2 = 2 kgv1 = 4 m/sv2 = 0
v′1 = m/s
5.Hard
A 0.4 kg ball hits a wall at 11 m/s and bounces straight back at 10 m/s. The contact lasts 40 ms. Find the magnitude of the impulse J the wall gives the ball.
m = 0.4 kgvin = 11 m/svout = 10 m/sΔt = 40 ms
J = N·s
6.Hard
A 15 g bullet is fired horizontally into a 2 kg block hanging from light strings 1.6 m long, and stays in it. The strings swing out to a largest angle of 20° from the vertical. Use g = 9.81 m/s². Find the speed v of the bullet before impact.
m = 15 gM = 2 kgL = 1.6 mθ = 20°g = 9.81 m/s²
v = m/s
Answer key
- 1. V = 1.167 m/s
- 2. v′ = 1.565 m/s
- 3. v′2 = 0.6667 m/s
- 4. v′1 = 1.091 m/s
- 5. J = 8.4 N·s
- 6. v = 184.8 m/s
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