# Heat and internal energy

1. May 3, 2008

### caesius

1. The problem statement, all variables and given/known data
On his honeymoon, James Joule tested the conversion of mechanical energy into internal energy by measuring temperatures of falling water. If water at the top of a Swiss waterfall has a temperature of 10.0 degrees Celsius and then falls 50.0 m, what maximum temperature at the bottom could Joule expect?

2. Relevant equations

change in internal energy = mgh

3. The attempt at a solution

I'm sure this question is easy I must be missing something, the change in internal energy is mgh but we have no mass?

The answer is (10.0 + 0.117) but I don't see how this was found.

2. May 3, 2008

### olgranpappy

use
$$\Delta E = c M \Delta T$$
where c is the specific heat. the mass drops out.