Asked in PMC Practice Test 28 (2021) 2021Moderate

If momentum is increased by 20% then K.E. increase by :

Correct answer: A. 0.44

  • A. 0.44
  • B. 0.55
  • C. 0.66
  • D. 0.77

Explanation

If momentum is increased by 20%, then the kinetic energy increases by 44% or 0.44 The kinetic energy of an object is given by the equation KE = 1/2mv2, where KE is the kinetic energy, m is the mass of the object, and v is the velocity of the object. The momentum of an object is given by the equation p = mv, where p is the momentum, m is the mass of the object, and v is the velocity of the object. If the momentum is increased by 20%, then the new momentum is 1.2 times the old momentum. Therefore, p2 = 1.2p1. Using the equations for momentum and kinetic energy, we can derive the following equation: KE2 = 1/2m(v2)2 = 1/2m[(p2/m)2/m2] = 1/2(p22/m2). Substituting p2 = 1.2p1, we get KE2 = 1/2[(1.2p1)2/m2] = 1.44(1/2)(p12/m2) = 1.44KE1. Therefore, if momentum is increased by 20%, then the kinetic energy increases by 44%

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