Question

A body of mass 2 kg is sliding down on an inclined plane of $\theta ={53}^0$. What is the time taken by the body to reach the ground if the length of the inclined plane is 10m? ($g=10m{s}^{-2}$ and ${\mu }_k=0.5$ )

• A. $2$ sec
• B. $4$ sec
• C. $3$ sec
• D. $5$ sec

Answer 1

The correct option is A $2$ sec

Acceleration $a=gsin\theta -{\mu }_{k}gcos\theta =10\times \frac{4}{5}-0.5\times 10\times \frac{3}{5}=5m/s^2$

As, $s=\frac{1}{2}a{t}^2\Rightarrow t=\sqrt{\frac{2s}{a}}=\sqrt{4}=2sec$