QUESTION 2
An object of mass $m = 1$ kg, moving horizontally, hits a windscreen travelling in the opposite direction. The
windscreen is tilted at an angle $\theta = \frac{\pi}{4}$ rad to the horizontal. A force $F$ acts on the object, for a duration of
$T$ seconds, such that $F$ is constant in magnitude and is directed normal (perpendicular) to the windscreen.
At impact, the object has speed $v_i$, and the windscreen has speed $v_w = 2v_i$. Impose a frame of reference in
which the windscreen is stationary, and in which gravity acts in the usual downward direction. Show that,
if the object bounces vertically upwards off the windscreen at $2 \text{ ms}^{-1}$, then
$T = \frac{3v_i - 2}{g}$,
where $g$ is the gravitational acceleration.
