# Differential equation for unbalanced rotating force

## Homework Statement

##M\ddot{y} + k_{eq}y = me\omega^2\sin(\omega t)##

What is ##m##?

## The Attempt at a Solution

In the ODE above, ##M## is the total mass of the problem, correct? For instance, if we had a cantilever beam, ##M = m_b + m_m(0.23)## where ##m_b## is the mass of the beam and ##m_m## is the mass of the motor.

Is ##m## the mass of the motor causing the unbalance or is it the mass of the whole system as well?

OldEngr63
Gold Member
Is there no figure associated with this problem?

To just start with the ODE given, I think that the only truly correct answer is to say that
m is the 13th letter of the alphabet.

The problem is that there are many physical systems that give rise to a particular describing differential equation. To start with the ODE and ask what the parameters are is pure nonsense.