Answer:
b) 188 N
c) 275 N
Explanation:
Draw a free body diagram of the box. There are four forces:
Applied force F at an angle θ
Weight mg pulling down
Normal force Fn pushing up
Friction force Ff pushing left
(b)
Sum of the forces in the x direction:
∑F = ma
F cos θ − Ff = 0
Ff = F cos θ
Ff = 200 cos 20°
Ff = 188 N
(c)
Sum of the forces in the y direction:
∑F = ma
F sin θ + Fn − mg = 0
Fn = mg − F sin θ
Fn = (35)(9.8) − 200 sin 20°
Fn = 275 N
