KINETIC ENERGY

The Kinetic Energy of Objects – Test it!

The Kinetic Energy of Objects – Test it!

Physics GCSE science revision- Kinetic energy

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.

Physics GCSE science revision- Kinetic energy2. 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.

Point of swing

Amount of kinetic energy

Amount of gravitational potential energy

Highest point on left hand side
Lowest central point
Highest point on right hand side

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.

Physics GCSE science revision- Kinetic energy3. 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)

Point of swing

Amount of kinetic energy

Amount of gravitational potential energy

Highest point on left hand side

Minimum

Maximum

Lowest central point

Maximum

Minimum

Highest point on right hand side

Minimum

Maximum

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