Question

In an 88 s interval, 588 hailstones strike a
glass window of area 0.624 m2
at an angle 20◦
to the window surface. Each hailstone has a
mass of 6 g and speed of 12.1 m/s.
If the collisions are elastic, find the average
force on the window.
Answer in units of N
Don't round answer.

Answer 1

The impulse acting on a window

$$\Delta p=2Nmv\sin 20^{\circ}$$

The average force

$$F=\frac{\Delta p}{\Delta t}=\frac{2Nmv\sin 20^{\circ}}{\Delta t}$$

$$=\frac{2\times 588\times 0.006 \times 12.1\times \sin 20^{\circ}}{88}=0.027\:\rm N=27\: mN.$$