A steel ball of mass 0.080 kg0.080\text{ kg}0.080 kg is dropped from an electromagnet. It falls vertically and collides with a trapdoor, causing the trapdoor to swing downwards. Immediately before the collision, the ball is traveling with a speed of 3.5 m s−13.5\text{ m s}^{-1}3.5 m s−1.
The graph of the upward force acting on the ball against time during the collision is shown below:
Calculate the initial momentum p1p_1p1 of the ball just before it hits the trapdoor.
Use the graph to calculate the magnitude of the final momentum p2p_2p2 of the ball immediately after the collision.
The mass of the trapdoor is 125 g125\text{ g}125 g. Assuming the trapdoor is initially at rest, calculate the final speed vvv of the trapdoor immediately after the collision.