A boy takes 2 second to reach the maximum speed of 18 km/h from rest. What is the magnitude of his average acceleration ?

Explanation

Given : Time = 2 seconds
Maximum speed = 18 km/hr
Here initial velocity
u = 0,
`v = (v_("max")) = 18 km/h`
`= 18 xx (5)/(18) = 5 m//s,`
`t_(1) = 0, t_(2) = 2 ` seconds
`a_(av) = (v-u)/(t_(2) - t_(1)) = (Deltav)/(Delta t)`
so, `a_(av) = (5 . 0)/(2) = 2.5 m//s^(2)`