Question

A block of mass 2.0 kg is pulled up on a smooth incline of angle ${30}^{\circ }$ with the horizontal. If the block moves with an acceleration of $1.0m/s^2$. The power delivered by the pulling force at a time 4.0 s after the motion starts is 12 K. Find the value of K.

Answer 1

$a=1m/s^2$

$v=u+at=0+1\times 4=4m/s$

$F-mg\sin \theta =ma$

$⟹F=m(a+g\sin \theta )=2(1+10\times \frac{1}{2})=12N$

$Power=P=Fv=12\times 4$

$⟹P=48W=12K$

$⟹K=4$