# PE Farmer

1. Oct 25, 2005

### Izekid

A farmer uses a pump to lift water from a river to a arable land who lies 5.0m higher than the river. The pump exhaust an electrical effect of 1.0kW but only 65% is used to do the lifting. ok A) I have resolved the lifting work is 0,65*60 = 39kJ

But B) is harder,,,, how much water is pumped up during a minute ...?

2. Oct 25, 2005

### Päällikkö

In A) you've apparently solved how much work is used to lifting the water a minute.
During this minute, how much water is lifted?
Is the anwer in kg or m3? Doesn't really matter, you know their relation.

What is the energy required to lift a ball of mass m to height h?

3. Oct 25, 2005

### mrjeffy321

You know that 65% of the pumps power (1 kW) is used to lift water.
This means that every second, 650 J of energy is used by the pump to list water, multiply by 60 to get energy per minute.
You know how much energy it will take to lift m kilograms of water h distance up against gravity g (mgh), since in this problem h and g are givens/constants, so just solve for m.