1.Easy
A 900 kg car moving at 20 m/s runs into a stationary 1500 kg car. The cars lock together. Find their common velocity v′ just after the collision (positive in the first car’s direction).
m1 = 900 kgv1 = 20 m/sm2 = 1500 kgv2 = 0 m/s
v′ = m/s
Momentum & collisions worksheet with answers
2.Easy
A 1400 kg car moving at 20 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 = 1400 kgv1 = 20 m/sm2 = 1300 kgv2 = 0 m/s
v′ = m/s
3.Medium
A 10 kg projectile moving horizontally at 17 m/s explodes into two fragments that move along the same line. The 6 kg fragment continues forwards at 63 m/s. Find the velocity v′2 of the 4 kg fragment (positive in the original direction).
M = 10 kgu = 17 m/sm1 = 6 kgv′1 = 63 m/sm2 = 4 kg
v′2 = m/s
4.Medium
An 11 kg projectile moving horizontally at 12 m/s explodes into two fragments that move along the same line. The 8 kg fragment continues forwards at 42 m/s. Find the velocity v′2 of the 3 kg fragment (positive in the original direction).
M = 11 kgu = 12 m/sm1 = 8 kgv′1 = 42 m/sm2 = 3 kg
v′2 = m/s
5.Hard
A 20 g bullet is fired horizontally into a 2.5 kg block hanging from light strings 1.7 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 = 20 gM = 2.5 kgL = 1.7 mθ = 15°g = 9.81 m/s²
v = m/s
6.Hard
A 1500 kg car runs into a parked 1200 kg car. The wrecks lock together and skid 21 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 = 1500 kgm2 = 1200 kgd = 21 mμ = 0.6g = 9.81 m/s²
v1 = m/s
Answer key
- 1. v′ = 7.5 m/s
- 2. v′ = 10.37 m/s
- 3. v′2 = −52 m/s
- 4. v′2 = −68 m/s
- 5. v = 134.3 m/s
- 6. v1 = 28.3 m/s
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