A horizontal force, just sufficient to move a body of mass 4kg lying on a rough horizontal surface, is applied on it. The coefficients of static and kinetic friction between the body and the surface are 0.8 and 0.6 respectively. If the force continues to act even after the body has started moving, the acceleration of the body (in `ms^(-2)`) is (take `g= 10 ms^(-2)`)

Options

A. 2
B. 4
C. 6
D. 8

Answer

A

Explanation

Force `F= (mu_(s)- mu_(k)) mg= (0.8 -0.6) xx 4 xx 10= 8N`
`therefore` Acceleration `=(F)/(m)= (8N)/(4kg) = 2ms^(-2)`