Medium
An athlete completes one round of a circular track of radius R in 40 seconds. What will be the displacement at the end of 1 minute 20 seconds?
Explanation
Explanation
1 minute 20 seconds = 80 seconds, which is exactly 2 complete rounds (2 x 40s). Completing a whole number of rounds returns the athlete to the starting point, so the net displacement is zero.
PRO TIP
Re-check your working by substituting the answer back into the original question.