1 A ball is thrown vertically upwards from ground level with an initial speed of \(15 \mathrm {~m} \mathrm {~s} ^ { - 1 }\). The ball has a mass of 0.6 kg . Assume that the only force acting on the ball after it is thrown is its weight.
- Calculate the initial kinetic energy of the ball.
- By using conservation of energy, find the maximum height above ground level reached by the ball.
- By using conservation of energy, find the kinetic energy and the speed of the ball when it is at a height of 3 m above ground level.
- State one modelling assumption which has been made.