A plane inclined at an angle at 30o to the horizontal has an efficiency of 50%. The force parallel to the plane required to push a load of 120 N uniformly up the plane is

A plane inclined at an angle at 30^o to the horizontal has an efficiency of 50%. The force parallel to the plane required to push a load of 120 N uniformly up the plane is

A 40âˆš3N
B 60N
C 120N
D 200N
E 240N

waec 1990 physics

The correct answer is C. 120N

E = M.A/V.R ; 50/100 = M.A/2

M.A = 1; L/E = 1

E = L = 120N

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