Finding friction force on a block pulled up a ramp at constant velocity

[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??



Please help...I've pondered over this prob and I'm confused as to what formulas to use, etc...

 

[willem2]

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.

 

[willem2]

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.

 

[w3390]

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