Question

A blocks is moved from rest through a distance of $4m$ along a straight line path. The mass of the blocks if $5kg$ and the force acting on it is $20N$. If the kinetic energy acquired by the block be $40J$, at what angle to the path the force is acting.

• A. ${30}^o$
• B. ${60}^o$
• C. ${45}^o$
• D. $Noneofthese$

Answer 1

The correct option is B ${60}^o$

Work done = increase in kinetic energy

$F\cos \theta .d=40$

$20\cos \theta \times 0.4=40$

$\theta ={\cos }^{-1}\left(\frac{1}{2}\right)={60}^o$

Hence, angle is ${60}^o$