Moon is revolving around the earth, work done by the earth on the moon is
Correct answer: B. zero
- A. positive
- B. zero
- C. negative
- D. none of these
Explanation
B. The formula for work done on a body is; W = F × d cos θWhere,F = the force of gravitation applied by the earth.d = displacement between the two bodiesθ = the angle between F and dWhen the moon revolves around the earth, there is a 90° angle between the displacement of the moon and the gravitational force exerted by the earth.Putting θ = 90° in the equation,W = F × d cos But, Cos 90° = 0So, W = 0
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About Work
Work is done when a force produces displacement, with its value determined by the component of force along the displacement. The topic covers positive, negative and zero work, work by variable forces from force-displacement graphs, and the connection between net work and change in kinetic energy.
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