The bus is going with an acceleration of 2 m/s^2. What is the time frame during which the velocity of the bus increases by 72 km/h

Answer 1

Let

a = 2m/s² be the bus's acceleration,

v = 72 km/h = 72×1000m/3600s = 20 m/s be the desired increase in velocity.

In general, if given a time period t, then in the time t the bus's speed increases by the amount a×t.

Therefore we need time t satisfying

at = v

So

t = v/a = 20/2 = 10s

In other words, in 10 seconds the bus's speed will by increased by 72km/h.