force on a lifted object

**yyttr2** · Nov28-09, 08:34 PM

Is the force done on a lifted object equal the weight of the object in newtons times the height lifted?
F=mgh?
I would have used this but I noticed it was the same equation for gravitational potential energy (or just potential energy)...So I thought I would ask you all after failing to find it online.

**Doc Al** · Nov28-09, 08:44 PM

Originally Posted by yyttr2

Is the force done on a lifted object equal the weight of the object in newtons times the height lifted?

I suspect you meant work instead of force.

F=mgh?
I would have used this but I noticed it was the same equation for gravitational potential energy (or just potential energy)...So I thought I would ask you all after failing to find it online.

Yes, the work you must do to lift an object equals the increase in gravitational potential energy.

**yyttr2** · Nov28-09, 08:59 PM

no, no I was talking about force. I am trying to find the change in gravitational potential energy from a 2.0 object being lifted 3.5 meters.
So I thought I would find Ke at the bottom.

$LaTeX Code: \\sum w=\\Delta ke$

W=F.d

So I want to know if F=mgh
:)

If I am completely full of crap and doing it wrong please tell me o.O

**Doc Al** · Nov28-09, 09:05 PM

Originally Posted by yyttr2

W=F.d

So I want to know if F=mgh

No, F = mg (the weight). (Assuming you are doing the minimum work to overcome gravity.)

So W = Fd = mgh.

**yyttr2** · Nov28-09, 09:08 PM

oh, duh xD I feel stupid now. thank you.