A group of migrating birds are flying in the sky. If they experience wind in the same direction of their motion, then the work done by the wind on birds will be
Correct answer: C. Positive.
- A. Zero.
- B. Infinite.
- C. Positive.
- D. Negative.
Explanation
The correct answer is that the work done by the wind on the birds is positive. Work is calculated as the product of force and displacement in the direction of the force. Since the wind is aiding the birds' motion by blowing in the same direction they are flying, the work done is positive. The option 'zero' is incorrect because the force and displacement are not perpendicular. The option 'infinite' is not realistic as both the force and displacement are finite. The option 'negative' is incorrect because the wind is not opposing the birds' motion.
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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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