Determine an expression, in terms of $u$, $v$ and $t$, for the area below the graph.
State the quantity whose value is given by the area under the graph.
A ball is kicked at $15\,\text{m s}^{-1}$ at an angle of $60^{\circ}$ to the horizontal ground. It then hits a vertical wall at the instant when the ball’s path becomes horizontal, as shown in Fig. 2.2. Take air resistance to be negligible.
Using the vertical motion of the ball, calculate the time needed to reach the wall.
Explain why the ball’s horizontal velocity component remains unchanged as it travels to the wall.
Show that, on reaching the wall, the ball has a horizontal velocity of $7.5\,\text{m s}^{-1}$.
The mass of the ball in (b) is $0.40\,\text{kg}$. It stays in contact with the wall for $0.12\,\text{s}$ and rebounds horizontally at a speed of $4.3\,\text{m s}^{-1}$. Use the result from (b)(iii) to calculate the change in momentum of the ball due to the collision.
Calculate the size of the average force exerted on the ball by the wall.