The coefficient of static friction between the m = 3.20-kg crate and the 35.0° incline of the figure below is 0.260. What minimum force vector F must be applied to the crate perpendicular to the incline to prevent the crate from sliding down the incline?

Question

The coefficient of static friction between the m = 3.20-kg crate and the 35.0° incline of the figure below is 0.260. What minimum force vector F  must be applied to the crate perpendicular to the incline to prevent the crate from sliding down the incline?

Henry · Answer

Wt. of crate = m * g = 3.2kg * 9.8N/kg = 31.36 N. Fp = 31.36*sin35 = 17.99 N. = Force parallel to the incline. F = Fp*cos35 = 17.99*cos35 = 14.74 N.