A car accelerates uniformly from 18 kmph to 72 kmph in 5 s. The acceleration of the car (in m/s2) is:

Answer: Option A

Initial speed = u = 18 km/hr = 5 m/s
Final speed = v = 72 km/hr = 20 m/s
acceleration a = (v-u)/t = (20 - 5)/5 = 3 m/s².