The coefficient of friction between the tyres and road is 0.4. The minimum distance covered before attaining a speed of `8 ms^(-1)` starting from rest is nearly ( take `g=10 ms^(-2)`)

Options

A. 8m
B. 4m
C. 10m
D. 16m

Answer

A

Explanation

(d) Retardation, `a=(mu mg)/(m)=mug=4ms^(-2)`
using, `v^(2)=u^(2)+2as`
`(8)^(2)=(0)^(2)+2(4)(s)`
`therefore s=8m`