When the speed of your car is halved, by what factor does its kinetic energy decrease?
Correct answer: B. 1/4
- A. 1/2
- B. 1/4
- C. 1/8
- D. 1/6
Explanation
If the speed is halved (keeping the mass same), the kinetic energy decreases, it becomes one-fourth (since kinetic energy is proportional to the square of velocity).
This question appeared on the NUMS 2021 paper, which you can sit online with every answer explained.
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About Kinetic Energy
Kinetic energy is the energy of motion, given for a nonrelativistic object by K = ½mv², so it depends on mass and the square of speed. Questions connect kinetic energy with work through the work energy theorem, calculate changes in kinetic energy, and distinguish it from momentum and potential energy.
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