Two cars moving in the same direction have speeds of 100 kmh-1 and 130 kmh-1 what is the velocity of the faster car as measured by an observer in the slower car?
A. 30 kmh-1 B. 130 kmh-1 C. 200 kmh[sup][/sup] D. 230 kmh-1
Correct Answer: A
Explanation
Since the cars are moving in the same direction, the velocity of a body A, Va,relative to another body B, Vb is given by V = Va - Vb ∴ the velocity of faster car is measured by the observer in the slower car is V = 130kmh-1 - 100 kmh-1 = 30 kmh-1