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Q: An object moving with the uniform velocity of 4m/s has a kinetic energy of 120J. Find the mass of the object?
  • A. 15N
  • B. 15kg
  • C. 19Pa
  • D. 15W
Correct Answer: Option B - Kinetic energy is directly proportional to the mass of the object and to the square of its velocity: K.E. = 1/2 m v² Here, m = ? and v = 4 ms-1 and K.E. = 120J Then, 120 = m×4×4/2 m = 15 kg
B. Kinetic energy is directly proportional to the mass of the object and to the square of its velocity: K.E. = 1/2 m v² Here, m = ? and v = 4 ms-1 and K.E. = 120J Then, 120 = m×4×4/2 m = 15 kg

Explanations:

Kinetic energy is directly proportional to the mass of the object and to the square of its velocity: K.E. = 1/2 m v² Here, m = ? and v = 4 ms-1 and K.E. = 120J Then, 120 = m×4×4/2 m = 15 kg