Question

The uniform block of width W and height H in the figure below rests on an inclined plane in static equilibrium. The plane is slowly raised until the block begins to tip over. Assume the tipping occurs before the block starts to slide. Find an expression for the angle θ at which the block is on the verge of tipping. (Use any variable or symbol stated above as necessary.)

Answer 1

mg is downward. cg is at H/2, w/2. So the point where mg is directly over the lower corner, (draw a sketch). TanTheta=h/2/w/2=h/w
and theta is that tipping angle.

Answer 2

TanTheta=tan^-1=W/H

Answer 3

is that right?

Answer 4

Depends on how you labeled the angle, bottom or top. Recheck your sketch to makecertain you have the tipping angle the one you want.