1.Easy
A 3.5 kg rifle, free to move, fires a 10 g bullet at 300 m/s. Both start at rest. Find the recoil speed V of the rifle.
M = 3.5 kgm = 10 gv = 300 m/s
V = m/s
Momentum & collisions worksheet with answers
2.Easy
A 700 kg car moving at 8 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 = 700 kgv1 = 8 m/sm2 = 1200 kgv2 = 0 m/s
v′ = m/s
3.Medium
A 10 kg projectile moving horizontally at 29 m/s explodes into two fragments that move along the same line. The 6 kg fragment continues forwards at 71 m/s. Find the velocity v′2 of the 4 kg fragment (positive in the original direction).
M = 10 kgu = 29 m/sm1 = 6 kgv′1 = 71 m/sm2 = 4 kg
v′2 = m/s
4.Medium
A 1.5 kg glider moving at 6 m/s makes a perfectly elastic head-on collision with a 0.5 kg glider at rest on a frictionless track. Find the velocity v′2 of the second glider after the collision.
m1 = 1.5 kgm2 = 0.5 kgv1 = 6 m/sv2 = 0
v′2 = m/s
5.Hard
A 0.6 kg ball hits a wall at 19 m/s and bounces straight back at 11 m/s. The contact lasts 50 ms. Find the average force Favg of the wall on the ball.
m = 0.6 kgvin = 19 m/svout = 11 m/sΔt = 50 ms
Favg = N
6.Hard
A 0.15 kg ball hits a wall at 25 m/s and bounces straight back at 14 m/s. The contact lasts 50 ms. Find the average force Favg of the wall on the ball.
m = 0.15 kgvin = 25 m/svout = 14 m/sΔt = 50 ms
Favg = N
Answer key
- 1. V = 0.8571 m/s
- 2. v′ = 2.947 m/s
- 3. v′2 = −34 m/s
- 4. v′2 = 9 m/s
- 5. Favg = 360 N
- 6. Favg = 117 N
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