Engineering Statics

E-23


Determine the force P required for bringing the block A to the verge of moving upward. Let WA=300 lb, WB=120 lb, θ=30 deg. and the static coefficients of friction, μ, at surfaces 1, 2 and 3 by 0.30.


The FBD of the block A and wedge B are drawn separately.
The force equation in the x direction is written for block B.
The equation is simplified by substituting the values for the sine and 
cosine.
The force equation in the y direction is written for block B.
The equation is simplified by substituting the values for the sine and 
cosine.