1.Easy
A 1900 kg car moving at 7 m/s runs into a stationary 900 kg car. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).
m1 = 1900 kgv1 = 7 m/sm2 = 900 kgv2 = 0 m/s
v′ = m/s
Momentum & collisions worksheet with answers
2.Easy
A 6 kg rifle, free to move, fires a 12 g bullet at 700 m/s. Both start at rest. Find the recoil speed V of the rifle.
M = 6 kgm = 12 gv = 700 m/s
V = m/s
3.Medium
An 8 kg projectile moving horizontally at 27 m/s explodes into two fragments that move along the same line. The 4 kg fragment continues forwards at 65 m/s. Find the velocity v′2 of the 4 kg fragment (positive in the original direction).
M = 8 kgu = 27 m/sm1 = 4 kgv′1 = 65 m/sm2 = 4 kg
v′2 = m/s
4.Medium
A 4 kg glider moving at 5 m/s makes a perfectly elastic head-on collision with a 1 kg glider at rest on a frictionless track. Find the velocity v′2 of the second glider after the collision.
m1 = 4 kgm2 = 1 kgv1 = 5 m/sv2 = 0
v′2 = m/s
5.Hard
A 5 g bullet is fired horizontally into a 2.5 kg block hanging from light strings 0.6 m long, and stays in it. The strings swing out to a largest angle of 25° from the vertical. Use g = 9.81 m/s². Find the speed v of the bullet before impact.
m = 5 gM = 2.5 kgL = 0.6 mθ = 25°g = 9.81 m/s²
v = m/s
6.Hard
A 10 g bullet is fired horizontally into a 1 kg block hanging from light strings 1.8 m long, and stays in it. The strings swing out to a largest angle of 30° from the vertical. Use g = 9.81 m/s². Find the speed v of the bullet before impact.
m = 10 gM = 1 kgL = 1.8 mθ = 30°g = 9.81 m/s²
v = m/s
Answer key
- 1. v′ = 4.75 m/s
- 2. V = 1.4 m/s
- 3. v′2 = −11 m/s
- 4. v′2 = 8 m/s
- 5. v = 526.2 m/s
- 6. v = 219.7 m/s
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