figure 1

Example 3: Determine the magnitude of P needed to have impending tipping.

Given: W = 250 lb, a = 32 in., b = 72 in., h = 66 in, and ms = 0.4.


We begin by first calculating the maximum friction force that can occur at the contact surface.

figure 2 equation

For tipping to be the impending motion, the normal force must be located at the right edge of the block. In that case the moment due to P about the right edge will be equal to that due to weight of the block. Based on this equality, we determine P to be


Since P<Fs, the block is on the verge of tipping over with no possibility of sliding.