posted by Samantha .
he weight of the block in the drawing is 77.0 N. The coefficient of static friction between the block and the vertical wall is 0.490. (a) What minimum magnitude of the force is required to prevent the block from sliding down the wall? (Hint: The static frictional force exerted by 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.) Angle is 40 degrees.