1.Easy
A 1 kg trolley moving at 5 m/s runs into a 2 kg trolley at rest. After the collision the first trolley is at rest. Find the velocity v′2 of the second trolley.
m1 = 1 kgv1 = 5 m/sm2 = 2 kgv′1 = 0 m/s
v′2 = m/s
Momentum & collisions worksheet with answers
2.Easy
A 5.5 kg rifle, free to move, fires a 12 g bullet at 750 m/s. Both start at rest. Find the recoil speed V of the rifle.
M = 5.5 kgm = 12 gv = 750 m/s
V = m/s
3.Medium
A 4 kg projectile moving horizontally at 12 m/s explodes into two fragments that move along the same line. The 3 kg fragment continues forwards at 31 m/s. Find the velocity v′2 of the 1 kg fragment (positive in the original direction).
M = 4 kgu = 12 m/sm1 = 3 kgv′1 = 31 m/sm2 = 1 kg
v′2 = m/s
4.Medium
A 3 kg glider moving at 4 m/s makes a perfectly elastic head-on collision with a 1.5 kg glider at rest on a frictionless track. Find the velocity v′2 of the second glider after the collision.
m1 = 3 kgm2 = 1.5 kgv1 = 4 m/sv2 = 0
v′2 = m/s
5.Hard
A 0.15 kg ball hits a wall at 30 m/s and bounces straight back at 14 m/s. The contact lasts 40 ms. Find the magnitude of the impulse J the wall gives the ball.
m = 0.15 kgvin = 30 m/svout = 14 m/sΔt = 40 ms
J = N·s
6.Hard
At a crossing a 900 kg car travelling east at 8 m/s collides with a 1100 kg car travelling north at 24 m/s. The cars lock together. Find the speed v′ of the wreck just after the collision.
m1 = 900 kgv1 = 8 m/s (E)m2 = 1100 kgv2 = 24 m/s (N)
v′ = m/s
Answer key
- 1. v′2 = 2.5 m/s
- 2. V = 1.636 m/s
- 3. v′2 = −45 m/s
- 4. v′2 = 5.333 m/s
- 5. J = 6.6 N·s
- 6. v′ = 13.68 m/s
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