a i. Define potential energy.

ii. Identify differences between gravitational potential energy and elastic potential energy.

b. Seawater is trapped behind a dam at high tide and then released through turbines. The level of the water trapped by the dam falls 10.0 m until it is all at the same height as the sea.
i.  Calculate the mass of seawater covering an area of 1.4 × 10⁶ m² and with a depth of 10.0 m. (Density of seawater = 1030 kg m⁻³.)
ii. Calculate the maximum loss of potential energy of the seawater in i when passed through the turbines.
iii. The potential energy of the seawater, calculated in ii, is lost over a period of 6.0 hours. Estimate the average power output of the power station over this time period, given that the efficiency of the power station is 50%.