A plane inclined at an angle of 30o to the horizontal has an efficiency of 60%. The force parallel to the plane required to push a load of 120N uniformly up the plane is
-
A.
60N -
B.
100N -
C.
120N -
D.
200N -
E.
240N
Correct Answer: Option B
Explanation
V.R = (frac{1}{sin 30}) = 2
Efficiency = (frac{m.A}{V.R}) x 100%
60 = (frac{120}{effort}) x (frac{1}{2}) x 100
Effort = 100N