Question

1. A car starts motion from rest and then moves with velocity
72Km/h. The average velocity of car is
a) 10m/s (b) 20m/s (c) 5m/s
(d) 15m/s
​

Answer 1

Answer:

(b) 20 m/s is the answer, according to the given question

Explanation:

Initial velocity, u = 0, .i.e. at rest

Final velocity, v = 72 kmph = 20 m/s

Consider displacement travelled to be x metres.

Then, the average velocity is given by the equation

                          v(avg) = (total displacement) ÷ (total time taken)

Also, since we can find the time taken to cover displacement x,

                      velocity, v = displacement ÷ time

                   therefore, time = displacement ÷ velocity

Accordingly,

                v(avg) = $\frac{x}{\frac{x}{20} }$ = $\frac{20x}{x}$ = 20 m/s

Hope it helps!