Question

A body is sliding down an inclined plane forming an angle ${30}^0$ with the horizontal. If the coefficient of friction is 0.3, its displacement after 3 seconds is

• A. 78.4 m
• B. 44.15m
• C. 10.575 m
• D. Zero

Answer 1

The correct option is C 10.575 m

Forces acting on the body along the plane is:
$ma=mgsin\theta -\mu mgcos\theta$
$a=g(sin\theta -\mu cos\theta )=9.8(sin{30}^o-0.3(cos{30}^o\left)\right)=2.356m/s^2$
Displacement in 3 seconds$=\frac{1}{2}a{t}^2=0.5\left(2.356\right)\left(9\right)=10.575m$