In marathon race, a runner, while moving, is facing a wind from the opposite direction. The work done by the wind on the runner will be
Correct answer: D. Negative.
- A. Zero.
- B. Infinity.
- C. Positive.
- D. Negative.
Explanation
In a marathon race, the runner is moving against the wind, which means the wind exerts a force opposite to the runner's motion. When the force and displacement are in opposite directions, the work done is negative. Thus, the work done by the wind on the runner is negative. The other options are incorrect because: Zero work would mean no force in the direction of motion, positive work would mean assistance in the motion, and infinite work is not feasible in this scenario.
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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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