Question

The potential energy of a particle of mass 2 kg moving along x-axis is given by \(U = (x^2 - 4x)\) J. The force acting on it at \(x = 3\) m is:

• A. 2 N
• B. -2 N
• C. 4 N
• D. -4 N

Hint:

Force is the negative gradient of potential energy.

Answer 1

The Correct Option is B

\[ F = -\frac{dU}{dx} = -(2x - 4) = -2x + 4 \] At \(x=3\): \[ F = -6 + 4 = -2\ \text{N} \]