State how force is related to momentum.
A rigid bar with mass $450\,\text{g}$ is supported horizontally by two supports, A and B, as shown in Fig. 3.1. Support A lies $45\,\text{cm}$ from the bar’s centre of gravity $C$, while support B is $25\,\text{cm}$ from $C$. A ball of mass $140\,\text{g}$ drops vertically onto the bar and strikes it $50\,\text{cm}$ from $C$, as shown in Fig. 3.1. Fig. 3.2 shows how the ball’s velocity $v$ changes with time $t$ before, during and after the impact.
While the ball is touching the bar, use Fig. 3.2 to determine how much momentum the ball changes by.
For the interval while the ball is in contact with the bar, use Fig. 3.2 to show that the force from the ball on the bar is $33\,\text{N}$.
For the period when the ball is in contact with the bar, use the information in Fig. 3.1 and (b)(ii) to calculate the force produced on the bar by support A.
For the period when the ball is in contact with the bar, calculate the force exerted on the bar by support B.