Q$30.$

A $3\mathrm{.}0kg$ object is in simple harmonic motion in one dimension and moves according to the equation

$x(t)=(5\mathrm{.}0m)cos[(\frac{}{3}ra\frac{d}{s})t-\frac{}{4}$rad$]$

where $t$ is in seconds. How much time is needed for the object to move from its equilibrium position $)=(0$ to a position where its potential energy is half the total energy?

A$)0\mathrm{.}75s$

B$)0\mathrm{.}25s$