How Much Force is Needed to Move a Block on a Wall?

[james2mart]

The weight of the block in the drawing (SEE ATTACHMENT) is 64.4 N. The coefficient of static friction between the block and the vertical wall is 0.580.

(a) What minimum force is required to prevent the block from sliding down the wall? (Hint: The static frictional force exerted on the block is directed upward, parallel to the wall.)



(b) What minimum force is required to start the block moving up the wall? (Hint: The static frictional force is now directed down the wall.)

I can't figure this out...

 

[member 553083]

a) The minimum force required to prevent the block from sliding down the wall is 37.52 N. b) The minimum force required to start the block moving up the wall is 37.52 N.