Question

A force of 10 N is applied on an object of mass 1 kg for 2s, which was initially at rest. What is the work done on the object by the force ?

• A. $200J$
• B. $20J$
• C. $16J$
• D. $180J$

Answer 1

The correct option is A $200J$

From Newton's Second Law
$F=ma10=1\times aa=10m/s\text{Velocity after 2 sec is}v=u+at=0+10\times 2v=20m/s\text{u is zero since the object is initially at rest}\text{K.E after 2 sec will be}K.E=\frac{1}{2}m{v}^2=\frac{1}{2}\times 1\times 20\times 20=\frac{400}{2}=200J\text{Initially body was at rest, so initial}\text{K.E = 0}\text{From the work energy theorem}w=ChangeinK.E(200-0)=200J$