Which one of the following is non-conservative?
Correct answer: D. all of these
- A. friction
- B. tension in string
- C. air resistance
- D. all of these
Explanation
Here's why each option is correct:(a) Friction: When objects rub against each other, friction causes energy to be converted into thermal energy (heat). This lost energy cannot be fully recovered as usable work, making it a non-conservative force.(b) Tension in string: While tension in an ideal string might seem conservative as the work done seems independent of the path, real-world strings have internal friction that dissipates energy as heat, making it non-conservative.(c) Air resistance: Similar to friction, air resistance acts against an object's motion, converting kinetic energy into thermal energy. This energy loss makes air resistance a non-conservative force.
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About Work and Energy
Work transfers energy when a force causes displacement, while kinetic energy, gravitational potential energy and power describe motion, position and the rate of energy transfer. The work-energy theorem links net work with change in kinetic energy, and efficiency accounts for energy losses rather than treating them as energy destruction.
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