Q1. What is the frequency shift of a 68 police radar signal when it reflects off a car moving at 117? (Radar waves travel at the speed of light.)
Express the answer using two significant figures.
Q2. As part of a safety investigation, two 1400 cars travelling at 18 are crashed into different barriers. Find out the average forces exerted on (a) car that hits a line of water barrels and takes 1.8 to stop, and (b) car that hits a concrete barrier and takes 0.4 to stop.