Hi there!
We know that the MAXIMUM static friction force to be overcome is:
Fs (Force of Static Friction) = μN (Normal Force)
The normal force is equal to the weight of the block AND the vertical component of the applied force, so:
N = Mg + Fasinθ
Plug in the given values:
N = 26.8(9.81) + (89.2)sin(38) = 317.825 N
Multiply by the force of static friction to derive the static force:
0.74 * 317.825 = 325.191 N <-- MAXIMUM STATIC FRICTION FORCE
The force applied, if not greater than this value, will result in an EQUAL and OPPOSITE static frictional force. Thus:
Fs = Horizontal component of the applied force
Fs = 89.2cos(38) = 70.291 N
