2 A ball of mass 0.6 kg is thrown vertically upwards from ground level with an initial speed of \(14 \mathrm {~m} \mathrm {~s} ^ { - 1 }\).
- Calculate the initial kinetic energy of the ball.
- Assuming that no resistance forces act on the ball, use an energy method to find the maximum height reached by the ball.
- An experiment is conducted to confirm the maximum height for the ball calculated in part (b). In this experiment the ball rises to a height of only 8 metres.
- Find the work done against the air resistance force that acts on the ball as it moves.
- Assuming that the air resistance force is constant, find its magnitude.
- Explain why it is not realistic to model the air resistance as a constant force.