The sum of Kinetic Energy and Potential Energy is always constant provided:
Correct answer: B. There is no force of friction involved during the motion of the body
- A. There is some force of friction involved during the motion of the body
- B. There is no force of friction involved during the motion of the body
- C. There is greater force of friction involved during the motion of the body
- D. Both; there is some force of friction involved during the motion of the body & no force of friction involved during the motion of the body
- E. None of the above
Explanation
The principle of conservation of mechanical energy states that the total mechanical energy in a system remains constant when only conservative forces are acting. Conservative forces, like gravity, do not dissipate energy as heat, whereas non-conservative forces, such as friction, do. Therefore, in the presence of friction, mechanical energy is not conserved as it is converted into other forms, primarily heat. This makes Option B correct, as it specifies the absence of friction. Other options incorrectly assume that energy conservation is possible with friction or provide contradictory or non-applicable scenarios.
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About Potential Energy
Potential energy is energy stored because of position or configuration, including gravitational potential energy near Earth's surface and elastic energy in a stretched or compressed spring. Questions use changes in potential energy and conservation of mechanical energy, while distinguishing a chosen reference level from an absolute zero of energy.
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