STANDARDPhysics-Work, Energy and Power
STANDARD Physics Work Done by a Constant Force MCQ Question
Type: MCQ-conceptual-Medium-Class 11
A body is being raised to a height h from the surface of earth. What is the sign of work done by applied force and gravitational force respectively?
A
Positive, Positive
B
Positive, Negative
C
Negative, Positive
D
Negative, Negative
Correct Answer
Option B
Detailed Explanation
Work done, W = F·d = Fdcosθ, where θ is the angle between the force F and displacement d. As the body moves along the direction of applied force, θ = 0°, W = Fdcos0° = Fd. It is positive. As the body moves in a direction opposite to the gravitational force which acts vertically downwards, θ = 180°, W = Fdcos180° = -Fd. It is negative.
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