1.Easy
A 3.5 kg rifle, free to move, fires a 4 g bullet at 800 m/s. Both start at rest. Find the recoil speed V of the rifle.
M = 3.5 kgm = 4 gv = 800 m/s
V = m/s
Momentum & collisions worksheet with answers
2.Easy
A 4.5 kg rifle, free to move, fires a 15 g bullet at 500 m/s. Both start at rest. Find the recoil speed V of the rifle.
M = 4.5 kgm = 15 gv = 500 m/s
V = m/s
3.Medium
A 5 kg glider moving at 4 m/s makes a perfectly elastic head-on collision with a 0.5 kg glider at rest on a frictionless track. Find the velocity v′2 of the second glider after the collision.
m1 = 5 kgm2 = 0.5 kgv1 = 4 m/sv2 = 0
v′2 = m/s
4.Medium
A 12 kg projectile moving horizontally at 27 m/s explodes into two fragments that move along the same line. The 5 kg fragment continues forwards at 35 m/s. Find the velocity v′2 of the 7 kg fragment (positive in the original direction).
M = 12 kgu = 27 m/sm1 = 5 kgv′1 = 35 m/sm2 = 7 kg
v′2 = m/s
5.Hard
A 0.6 kg ball hits a wall at 26 m/s and bounces straight back at 12 m/s. The contact lasts 50 ms. Find the magnitude of the impulse J the wall gives the ball.
m = 0.6 kgvin = 26 m/svout = 12 m/sΔt = 50 ms
J = N·s
6.Hard
A 1200 kg car runs into a parked 1900 kg car. The wrecks lock together and skid 14.5 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 = 1200 kgm2 = 1900 kgd = 14.5 mμ = 0.6g = 9.81 m/s²
v1 = m/s
Answer key
- 1. V = 0.9143 m/s
- 2. V = 1.667 m/s
- 3. v′2 = 7.273 m/s
- 4. v′2 = 21.29 m/s
- 5. J = 22.8 N·s
- 6. v1 = 33.75 m/s
Full step-by-step solutions: practise this topic on examproblems.com.