physics
posted by mike .
A 14.0kg chair is at rest on a flat floor. The coefficient of static friction between
the chair and the floor is 0.450. A person tries to move the chair by pushing on the
chair with a force directed at an angle of 30„a below the horizontal. What is the
minimum force that the person must apply in order to move the chair?

Wc = m*g = 14kg * 9.8N/kg = 137.2 N. =
Wt. of chair.
Fc = 137.2 N. @ 0o = Force of chair.
Fp = 137.2*sin(0) = 0 = Force Parallel
with floor.
Fv=137.2*cos(0) + Fap*sin(30)
Fv=137.2  0.5Fap. =Force perpendicular to floor. = Normal.
Fn = Fap*cos(30)FpFs = m*a.
Fap00.45(137.20.5Fap) = m*0 = 0
Fap61.74+0.225Fap = 0
0.775Fap61.74 = 0
0.775Fap = 61.74
Fap = 79.7 N @ (30o).