2. A pump raises water from a well 12 metres below the ground and ejects the water through a pipe of diameter 10 cm at a speed of \(6 \mathrm {~ms} ^ { - 1 }\).
Given that the mass of \(1 \mathrm {~m} ^ { 3 }\) of water is 1000 kg ,
- find, in terms of \(\pi\), the mass of water discharged by the pipe every second,
- find in kJ , correct to 3 significant figures, the total mechanical energy gained by the water per second.