Question

A body of mass $15kg$ moving with a velocity of $10m{s}^{-1}$ is bought to rest. The work done by the brake is

• A. $-250J$
• B. $-500J$
• C. $-750J$
• D. $-1000J$

Answer 1

The correct option is C $-750J$

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

$W=\frac{1}{2}\times 15\times (0^2-{10}^2)$

$W=-750J$

Hence, option $C$ is correct answer.