Question

A compressed spring is held near a small toy car of mass $0.15kg$. On the release of the spring, the toy car moves forward with a velocity of $\raisebox{1ex}{$10m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$. Find the potential energy of the spring.

Answer 1

Step 1: Given:

Mass=$0.15kg$

Velocity=$\raisebox{1ex}{$10m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$

Step 2: To find the kinetic energy of a toy car:

Formula used:$Kineticenergy=\frac{1}{2}\times mass\times {\left(velocity\right)}^2$

$$\begin{gathered} E_K=\frac{1}{2}m{v}^2 \\ =\frac{1}{2}(0.15){\left(10\right)}^2 \end{gathered}$$

$=7.5J$

Step 3: To find the potential energy of spring:

Since the potential energy of spring is changed to the kinetic energy of the car.

The kinetic energy of the car = Potential energy of spring

$E_P=7.5J$

Therefore, the potential energy of spring is $7.5J$.