3 A pump is being used to empty a flooded basement.
In one minute, 400 litres of water are pumped out of the basement.
The water is raised 8 metres and is ejected through a pipe at a speed of \(2 \mathrm {~ms} ^ { - 1 }\).
The mass of 400 litres of water is 400 kg .

1. Calculate the gain in potential energy of the 400 litres of water.
2. Calculate the gain in kinetic energy of the 400 litres of water.
3. Hence calculate the power of the pump, giving your answer in watts.