If velocity is double, then:
Correct answer: D. Momentum increases 2 times and K.E increases 4 times
- A. Momentum increases 4 times and K.E increases 2 times
- B. Momentum and K.E remain the same
- C. Momentum increases 2 times and K.E increases constantly
- D. Momentum increases 2 times and K.E increases 4 times
Explanation
Option D is correct. When velocity is doubled, the momentum, which is calculated using p = m.v, increases by a factor of 2. The kinetic energy, calculated using K.E = 1/2 m.v2, increases by a factor of 4 because the velocity is squared in the formula. Option A is incorrect because it reverses the effects on momentum and kinetic energy. Option B is incorrect because both physical quantities do change with velocity. Option C misunderstands the relationship between velocity and kinetic energy, which increases fourfold rather than remaining constant.
This question appeared on the UHS MDCAT 2010 paper, which you can sit online with every answer explained.
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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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