Posted by Nick on Thursday, April 11, 2013 at 12:01pm.
Your written homework will be graded entirely on the clarity and completeness of
your derivation. No credit will be awarded for a final answer without a derivation.
As usual, simplify your final answers as much as possible.
A giant Pez dispenser of mass m rests on a ladder of mass M and length L. The
ladder is propped at an angle to the horizontal. The coefficient of static friction
between the ground and the ladder is S and the wall against which the ladder is
resting is frictionless. The Pez is a distance d up from the bottom of the ladder.
A) Draw an extended freebody diagram, showing all the forces acting on the
ladder and where they are acting.
B) What is the maximum mass m of Pez for which the ladder will not slip?
C) At a certain angle your expression for m becomes infinite. What is that
angle?
D) At another angle your expression for m becomes less than zero (negative).
Over what range of angles is the value of m negative?
E) What is the physical significance of these peculiar values of m?

physics  Nick, Thursday, April 11, 2013 at 12:31pm
If your browser can't load certain text, the box after angle is theta, and the coefficient of static friction is u sub s