JEE Main 2022 · 28 Jul · Shift 2, Physics question 25

The potential energy of a particle of mass 4 kg in motion along the $x$-axis is given by $U=4(1-\cos4x)$ J. The time period of the particle for small oscillation $(\sin\theta\simeq\theta)$ is $\left(\dfrac\pi K\right)$ s. The value of K is ______.