Multiple choice

The momentum of a body is increased by 25%. The kinetic energy is increased by about ______.

  1. 34%

  2. 56%

  3. 65%

  4. 5%

  5. 23%
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Kinetic energy of body is K = p2/2m Where p is the momentum and m is the mass of a body respectively ... k proportional to p2 When the momentum of a body is increased by 25%, its momentum will become P' = p + (25/100)p = (125/100)p = (5/4)p ... k'/k = p' 2/p2 = (5/4)2 = 25/16 or k' = (25/16)k Percentage increase in the kinetic energy of the body = (k ' -k)/k = {(25/16)k - k}/k= (9/16) Χ 100 = 56%

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