# Mechanics - Friction on a Slope

• Mar 20th 2009, 09:53 AM
StaryNight
Mechanics - Friction on a Slope
I'm stuck on a mechanics question I have to do for homework:

A block of mass 4KG is at rest on a plane inclined at 35 degrees to the horizontal, under the action of a force of magnitude PN acting up the plane. The coefficient of friction between the block and the plane is 0.45. Find the range of possible values for P.

I've tried resolving the forces horizontally and vertically, but can't work out how i'm supposed to find a range of values.

Thanks
• Mar 20th 2009, 10:10 AM
Quote:

Originally Posted by StaryNight
I'm stuck on a mechanics question I have to do for homework:

A block of mass 4KG is at rest on a plane inclined at 35 degrees to the horizontal, under the action of a force of magnitude PN acting up the plane. The coefficient of friction between the block and the plane is 0.45. Find the range of possible values for P.

I've tried resolving the forces horizontally and vertically, but can't work out how i'm supposed to find a range of values.

Thanks

All you need to do is to find the value of P for which

minimum-the block doesnot fall down, ie: force required to stop (in this case the friction and P act in the same direction)

maximum- the force on whose application the the block doesnot go up (in this case friction will be down the plane opposite to P)