# Homework Help: HELP finding FORCE OF FRICTION?

1. Oct 26, 2009

### dagitt

HELP finding FORCE OF FRICTION????

1. I'm pulling a 4.24kg block UP a ramp.
2. The normal force is 9.21 N.
3. The "motion" force as it is being pulled up the ramp at constant velocity is 3.5 N.

What is the force of friction acting on the block??

2. Oct 26, 2009

### willem2

Re: HELP finding FORCE OF FRICTION????

Are you sure the normal force is 9.21N? That would be a quite steep ramp.
What exactly is the "motion" force? The velocity is constant, so the net force is 0.
The force that you use to pull must overcome both gravity and friction and has to be
much bigger than 3.5N to do that.

With nearly all slope problems you have to split the forces involved in components parallel and perpendicular to the slope.

3. Oct 26, 2009

### willem2

Re: HELP finding FORCE OF FRICTION????

Are you sure the normal force is 9.21N? That would be a quite steep ramp.
What exactly is the "motion" force? The velocity is constant, so the net force is 0.
The force that you use to pull must overcome both gravity and friction and has to be
much bigger than 3.5N to do that.

With nearly all slope problems you have to split the forces involved in components parallel and perpendicular to the slope.

4. Oct 26, 2009

### w3390

Re: HELP finding FORCE OF FRICTION????

Ya, with a normal force like that, the plane must be inclined around 77 degrees. That's steep!