The kinetic energy of a body is doubled when its
Correct answer: C. speed is increased by a factor of the square root of two
- A. mass is halved
- B. speed is doubled
- C. speed is increased by a factor of the square root of two
- D. mass is doubled and speed halved
Explanation
Kinetic energy is half m v squared, so it scales with the square of the speed. Multiplying the speed by root 2 multiplies the energy by 2, whereas doubling the speed multiplies the energy by 4. The last option leaves energy at half its original value, since doubling m and quartering v squared gives a net factor of one half.
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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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