Question

A body is projected along a rough horizontal surface with a velocity $6\text{m/s}$. If the body comes to rest after travelling $9\text{m}$, then coefficient of sliding friction, is $(g=10{\text{m/s}}^2)$

• A. $0.5$
• B. $0.4$
• C. $0.6$
• D. $0.2$

Answer 1

The correct option is D $0.2$

Using newtons 2nd law
$F_{\text{net}}=ma$
Retardation $a=\frac{\mu mg}{m}=\mu g=10\mu$
Now, $0=u^2-2as$
or $0=\left(6^2\right)-2\left(10\mu \right)\left(9\right)$
$\therefore \mu =0.2$