Question

To lift a $5kg$ mass to a certain height, amount of energy spent is $245J.$ The mass was raised to a height of:

• A. $15m$
• B. $10m$
• C. $7.5m$
• D. $5m$

Answer 1

The correct option is D

$5m$

Step 1: Given data,

$mass=5kg$

Potential energy $=245J$

Step 2: Finding height,

The potential energy in terms of the acceleration due to gravity and height is,

$P.E.=mgh$

The acceleration due to gravity is $g=9.8m/s^2$.

Substituting the known values,

$$\begin{gathered} 245J=5kg\times 9.8m/s^2\times h \\ h=\frac{245}{5\times 9.8} \\ h=\frac{245}{49} \\ h=5m \end{gathered}$$

Thus, mass was raised to a height of $5m.$

Hence, option D is correct.