Which of the following options exemplify(ies) negative work done?Work done under a conservative forceII. Work done against the force of frictionIII. Work done under the influence of gravity
Correct answer: D. II and III
- A. I only
- B. II only
- C. I and II
- D. II and III
Explanation
The correct answer is Option D: II and III.II. Work done against the force of friction is negative because friction always acts in the opposite direction to the motion, meaning the force and displacement are in opposing directions.III. Work done under the influence of gravity can be negative when an object is being lifted up against gravity, as the force of gravity is acting in the opposite direction to the displacement.Option I, Work done under a conservative force, can be positive, negative, or zero depending on the specific situation, and thus does not inherently mean negative work.
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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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