# Find the total mechanical energy.

1. Nov 1, 2006

### YMasoud

Good day,
I found this question on the Web.

A piston in an engine moves back and forth over a distance of 2mm in SHM with a frequency of 120Hz. Find the total mechanical energy.

Is there a way to find the energy without knowing the piston's mass?
The answer provided is $$14 \mu~J$$

Many thanks,
YMasoud

2. Nov 1, 2006

### Staff: Mentor

I don't see how--the energy would be proportional to the mass (given fixed frequency and amplitude). Perhaps the mass is given elsewhere.

3. Nov 1, 2006

### nrqed

I don't see how. The total energy is ${1 \over 2} m \omega^2 A^2$.

4. Nov 1, 2006

### rsk

I've been looking for a way to do it without the mass and I can't see it....