Question

A constant force $F$ is applied to a body of mass $m$ moving with initial velocity $u$. If after the body undergoes a displacement $S$, its velocity becomes $v$, then the total work done is

• A. $m[v^2+u^2]$
• B. $\frac{m}{2}[u^2+v^2]$
• C. $\frac{m}{2}[v^2-u^2]$
• D. $m[v^2-u^2]$

Answer 1

Answer: (C)

$\frac{m}{2}[v^2-u^2]$

The work done is equal to the change in the kinetic energy of an object.

$Workdone=changeinkineticenergy=\frac{1}{2}m(v^2-u^2)$