1.Easy
A 1300 kg car moving at 25 m/s runs into a stationary 1300 kg car. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).
m1 = 1300 kgv1 = 25 m/sm2 = 1300 kgv2 = 0 m/s
v′ = m/s
Momentum & collisions worksheet with answers
2.Easy
A 2000 kg car moving at 11 m/s runs into a stationary 1400 kg car. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).
m1 = 2000 kgv1 = 11 m/sm2 = 1400 kgv2 = 0 m/s
v′ = m/s
3.Medium
A 10 g bullet is fired horizontally into a 3.5 kg wooden block hanging on light strings, and stays inside it. The block swings up until it is 21 cm higher than at the start. Use g = 9.81 m/s². Find the speed v of the bullet before impact.
m = 10 gM = 3.5 kgh = 21 cmg = 9.81 m/s²
v = m/s
4.Medium
A 4 kg projectile moving horizontally at 20 m/s explodes into two fragments that move along the same line. The 2 kg fragment continues forwards at 65 m/s. Find the velocity v′2 of the 2 kg fragment (positive in the original direction).
M = 4 kgu = 20 m/sm1 = 2 kgv′1 = 65 m/sm2 = 2 kg
v′2 = m/s
5.Hard
A 1400 kg car runs into a parked 1600 kg car. The wrecks lock together and skid 4 m before stopping. The coefficient of kinetic friction between tyres and road is 0.7. Use g = 9.81 m/s². Find the speed v1 of the first car just before the collision.
m1 = 1400 kgm2 = 1600 kgd = 4 mμ = 0.7g = 9.81 m/s²
v1 = m/s
6.Hard
At a crossing a 1200 kg car travelling east at 9 m/s collides with a 1800 kg car travelling north at 13 m/s. The cars lock together. Find the direction θ of the wreck just after the collision, measured north of east.
m1 = 1200 kgv1 = 9 m/s (E)m2 = 1800 kgv2 = 13 m/s (N)
θ = °
Answer key
- 1. v′ = 12.5 m/s
- 2. v′ = 6.471 m/s
- 3. v = 712.5 m/s
- 4. v′2 = −25 m/s
- 5. v1 = 15.88 m/s
- 6. θ = 65.22 °
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