Question

A body ascends a slope with a speed of $10m{s}^{-1}$. If $10$% of energy of the body is lost due to friction, the height to which the body will rise is (take $g=10m{s}^{-2}$)

• A. $0.5m$
• B. $4.5m$
• C. $3.5m$
• D. $2.0m$

Answer 1

The correct option is A $0.5m$

According to the work$-$ energy principle$,$

$P.E=K.E$

$mgh=1/2m{v}^2-105$ $($as $105J$ of body energy is lost due to friction$)$

$2gh=v^2-105m$

$2\left(10\right)h=v^2-105m$

$20h=100-105m$

$h=\left(100-105m\right)/20$

$h=\left(20-21m\right)/4$

This is the required expression for calculating the height$,$ where m is mass in kg$.$

Hence,

option $\left(A\right)$ is correct answer.