A 20kg mass is to be pulled up a slope inclined at 30° to the horizontal. If the efficiency of the plane is 75%. The force required to pull the load up the plane is J [g=10ms−²]

A. 87N
B. 73.5N
C. 133.3N
D. 533.2N

Correct Answer:

Option C – 133.3N

Explanation

V. R = 1/Sinθ
m = 20kg

V.R = 1/Sin30
= 2

Efficiency = 75%

Load = mg

= 20 x 10 = 200N

Efficiency = M.A/V.R×100
75/100 = M.A/2
M .A = 75×2/100
M. A = 1.5

Since M. A. = Load/Force
Force = 200/1.5
= 133.3N