Suppose a block of mass `1kg` is placed over a rough surface and a horizontal force `F` is applied on the block as shown in figure. Now, let us see what are the values of force of friction `f` and acceleration of the block a if the force `F` is gradually increased. Given that `mu_(s) =0.5,mu_(k) =0.4 and g=10m//s^(2)`

Explanation

Free body diagram of block is

`sumF_(y)=0`
` therefore` N-m =0 or N=mg=(1)(10)=10N
`f_(L)= mu_(s) " "N=(0.5)(10)=5N`
and `f_(k)=mu_(k)N=(0.4)(10)=4N`