What Forces Act on a Driven Pendulum?

cytochrome · Nov 6, 2012

Homework Statement

What is the net force done on a driven pendulum?

Fd=mk (driving force)
Fg=mg (Gravitational force)
Fr=? (Do I need to include this?)

Fnet = Fd + Fg = mk + mg

I'm not sure if I need to include the restoring force, which was not given in the problem but I know it is there.

haruspex · Nov 6, 2012

cytochrome said:

What is the net force done on a driven pendulum?

Force "done"? Unusual terminology. Does it really say that?

Homework Equations

Fd=mk (driving force)

Why is the driving force proportional to the mass of the pendulum? Or is this some other mass?

Fg=mg (Gravitational force)

Are you using g as a vector here? If not, you need to consider that not all the forces will be collinear.

Fr=? (Do I need to include this?)

Depends what it is. There certainly is another force somewhere, or the pendulum would drop like a stone.