Question

A piece of cork of mass 2.00 g tossed randomly on the surface of the lake. Cork is oscillating in the vertical with a period of 9.00 s and amplitude 2.00 cm. At time t = 0, the cork is in equilibrium position with potential energy equal to zero. Calculate the potential energy of the cork is at t = 2.01 s.

Answer 1

You'll have to know the angular velocity. \(\omega=\frac{2\pi r}{T}\)
For this, you'll have to sub r=0.02m, T=9s.
Then by \(v=r \omega cos {\omega t}\),
and \(E_p = E_{total} - E_k\), where \(E_{total}=E_{kmax}\) during the amplitude, you'll get potential energy.
Do you need further help?