A 20kg mass is to be pulled up a slope inclined at 30° to the horizontal. If 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
Explanation
V. R = (frac{1}{Sinθ})
m = 20kg
V.R = (frac{1}{Sin 30})
= 2
Efficiency = 75%
Load = mg
= 20 x 10 = 200N
Efficiency = (frac{M.A}{V.R} times 100)
75/100 = (frac{M.A}{2})
M .A = (frac{75 times 2}{100})
M. A = 1.5
Since M. A. = (frac{text{Load}}{text{Force}})
Force = (frac{200}{1.5})
= 133.3N
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