1. A chimpanzee is swinging in a tree. It has a mass of 60 kg.

a) It’s knocked out of the tree and hits the ground at a speed of 10 m/s. What was the momentum of the chimpanzee as it hit the ground?

b) Once the chimpanzee hits the ground it slows down and stops in 0.15 s. Calculate the force which was exerted by the ground on the chimpanzee.

2. A pendulum is swinging.

a) Complete the table below to show how much kinetic energy and how much gravitational potential energy it has at three specific points of its swing. Use either maximum of minimum.

b) The mass of the pendulum bob is 5 g and it’s travelling at a speed of 10 cm/s. Calculate its kinetic energy.

3. Two trains collide. Train A has a mass of 15,000 kg and is moving at a rate of 20 m/s before the collision. Train two is stationary and has a mass of 25,000 kg.

a) What was the total momentum before the collision took place?

b) Using this answer, calculate the velocity of the trains after the collision.

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ANSWERS

1. a) 60 x 10 = 600 kg m/s or Ns

b) / 0.15 = 4000 N

2. a)

b) 0.5 x 0.005 x 0.1² = 0.000025 J

3. a) Train A = 15000 x 20 = 300000

Train B = 25000 x 0 = 0

Total momentum = 300000 + 0 = 300000 kg m/s

b)300000 / (15000 + 25000) = 7.5 m/s