A car runs off the road and hits a stationery rock. Some glass pieces from the windscreen are projected forward and were found at an average distance of 15 meters from the car. The average height of the windscreen is 1.5 meters. Calculate the speed of the car at the time of impact.

Answer 1

first, that's stationary, since the rock is presumably not made of paper.

How long does it take the glass to fall 1.5 meters?

Then figure the horizontal speed using speed = distance/time.

Answer 2

0.5sec
16m/s