Question

A car moving with velocity of 36km/h accelerates uniformly at 2m/s² until it reaches a velocity of 54 km/h.the time taken is ?

Answer 1

The velocity $v$ of an object moving with a constant acceleration at any moment of time $t$ is given by the following formula:

$$v = v_0+at$$

where $v_0 =36km/h = 10m/s$ is the initial velocity of the car and $a = 2m/s^2$ is its acceleration. If we set $v = 54km/h = 15m/s$, we can find the time that was taken to come from $v_0$ to $v$:

$$t = \dfrac{v-v_0}{a} = \dfrac{15-10}{2} = 2.5s$$

Answer. 2.5 s.