1.Easy
A 1200 kg car moving at 8 m/s runs into a stationary 1600 kg car. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).
m1 = 1200 kgv1 = 8 m/sm2 = 1600 kgv2 = 0 m/s
v′ = m/s
Momentum & collisions worksheet with answers
2.Easy
A 2000 kg car moving at 17 m/s collides head-on with a 500 kg car moving at 5 m/s in the opposite direction. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).
m1 = 2000 kgv1 = 17 m/sm2 = 500 kgv2 = −5 m/s
v′ = m/s
3.Medium
A 14 kg projectile moving horizontally at 23 m/s explodes into two fragments that move along the same line. The 1 kg fragment continues forwards at 56 m/s. Find the velocity v′2 of the 13 kg fragment (positive in the original direction).
M = 14 kgu = 23 m/sm1 = 1 kgv′1 = 56 m/sm2 = 13 kg
v′2 = m/s
4.Medium
A 1.5 kg glider moving at 9 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 = 1.5 kgm2 = 4.5 kgv1 = 9 m/sv2 = 0
v′2 = m/s
5.Hard
A 0.2 kg ball hits a wall at 14 m/s and bounces straight back at 7 m/s. The contact lasts 20 ms. Find the magnitude of the impulse J the wall gives the ball.
m = 0.2 kgvin = 14 m/svout = 7 m/sΔt = 20 ms
J = N·s
6.Hard
A 12 g bullet is fired horizontally into a 1 kg block hanging from light strings 0.7 m long, and stays in it. The strings swing out to a largest angle of 15° from the vertical. Use g = 9.81 m/s². Find the speed v of the bullet before impact.
m = 12 gM = 1 kgL = 0.7 mθ = 15°g = 9.81 m/s²
v = m/s
Answer key
- 1. v′ = 3.429 m/s
- 2. v′ = 12.6 m/s
- 3. v′2 = 20.46 m/s
- 4. v′2 = 4.5 m/s
- 5. J = 4.2 N·s
- 6. v = 57.69 m/s
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