A body of mass 7.5 kg is to be pulled along a plane which is inclined at 30º to the horizontal. If the efficiency of the plane is 75%, what is the minimum force required to pull the body up the plane?
- A20.0N
- B50.0N
- C75.0N
- D5.0N
Explanation
Velocity ratio (VR) of an inclined plane = 1/sin(30°) = 2. Efficiency (η) = MA / VR => 0.75 = MA / 2 => MA = 1.5. Mechanical Advantage (MA) = Load / Effort, where Load = mg = 7.5 kg × 10 m/s² = 75 N. Therefore, Effort = 75 / 1.5 = 50.0 N.
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