1.Easy
A 1600 kg car moving at 5 m/s runs into a stationary 800 kg car. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).
m1 = 1600 kgv1 = 5 m/sm2 = 800 kgv2 = 0 m/s
v′ = m/s
Momentum & collisions worksheet with answers
2.Easy
A 600 kg car moving at 19 m/s runs into a stationary 500 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 = 19 m/sm2 = 500 kgv2 = 0 m/s
v′ = m/s
3.Medium
An 8 g bullet is fired horizontally into a 3 kg wooden block hanging on light strings, and stays inside it. The block swings up until it is 11 cm higher than at the start. Use g = 9.81 m/s². Find the speed v of the bullet before impact.
m = 8 gM = 3 kgh = 11 cmg = 9.81 m/s²
v = m/s
4.Medium
A 12 g bullet is fired horizontally into a 4 kg wooden block hanging on light strings, and stays inside it. The block swings up until it is 19 cm higher than at the start. Use g = 9.81 m/s². Find the speed v of the bullet before impact.
m = 12 gM = 4 kgh = 19 cmg = 9.81 m/s²
v = m/s
5.Hard
A 900 kg car runs into a parked 800 kg car. The wrecks lock together and skid 9.5 m before stopping. The coefficient of kinetic friction between tyres and road is 0.6. Use g = 9.81 m/s². Find the speed v1 of the first car just before the collision.
m1 = 900 kgm2 = 800 kgd = 9.5 mμ = 0.6g = 9.81 m/s²
v1 = m/s
6.Hard
A 0.2 kg ball hits a wall at 15 m/s and bounces straight back at 17 m/s. The contact lasts 20 ms. Find the magnitude of the impulse J the wall gives the ball.
m = 0.2 kgvin = 15 m/svout = 17 m/sΔt = 20 ms
J = N·s
Answer key
- 1. v′ = 3.333 m/s
- 2. v′ = 10.36 m/s
- 3. v = 552.4 m/s
- 4. v = 645.5 m/s
- 5. v1 = 19.98 m/s
- 6. J = 6.4 N·s
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