Question

A particle is released from rest at origin. It moves under influence of potential field $U=x^2-3x$, kinetic energy at $x=2$ is:

• A. 0 J
• B. 1.5 J
• C. 1 J
• D. 2 J

Answer 1

The correct option is D

2 J

At origin particle is at rest.

At $x=0\Rightarrow U=x^2-3x=0$ and $KE=0$

So, total energy = $U+KE=0$

$\to$ At x=2m,

$U=2^2-3\left(2\right)=-2J$

Total energy $=U+KE$

$0=-2+KE$

$\therefore KE=2J$