Question

A football coach starts at the 0-yard line (a) and walks to the 40-yard line in 3 minutes. (b) he turns around and walks to the 0-yard line in the next 2 minutes. (c) he turns around again and walks back to the 50-yard line in the next three minutes. (d) he turns around once more and walks back to the 25-yard line in the next two minutes, thus completing his 10 minutes of pacing. the coach's average velocity is

Answer 1

Average velocity = total displacement / total time

Total displacement is 25 yards.

Displacement is defined to be the change in the position of an object. Here displacement is 25 yards as firstly he walks 40 yards and again comes back 40 yards so he comes to original starting point. Now he again walks 50 yards and comes back 25 yards, so he is 25 yards from his starting position, hence displacement is 25.

Total time = 10 minutes

Average velocity = $\frac{25}{10}$ = 2.5 yards per minute.