Question

A block of mass 4kg is kept on a rough horizontal surface as shown in the figure.A horizontal force of 19.4N is just able to slide the block (a) Find the coefficient of static friction.(b) If a force of 16N acts then what is the frictional force acting on the block?

Answer 1

If $F=19.4N$

Just able to slide, then frictional force ($f$) is given by

$f=F=\mu N=\mu \left(4g\right)$

$\mu =\frac{F}{4g}=\frac{19.4}{4\times 9.8}=0.494\approx 0.5$

b) If $F_2=16N$ that is lower than limiting friction.

Then, in this case frictional force $=F_2=f=16N$