The spring above stretches 0.15 m when a 0.30 kg mass is hung from it. The spring is then stretched an additional 0.1 m from its equilibrium position and then released. Determine the spring constant of the spring?
Calculate the period of oscillation of this system.
Calculate the frequency of the oscillation.

Ahuge (essentially infinite) horizontal nonconducting sheet 10.0 cm thick has charge uniformly spread over both faces. the upper face carries +95.0 nc/m2 while the lower face carries -25.0 nc/ m2. what is the magnitude of the electric field at a point within the sheet 2.00 cm below the upper face? (ε0 = 8.85 × 10-12 c2/n · m2)