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Q: A boy of 50 kg mass climbs 45 stairs in 10 seconds. If the height of each stair is 16cm then find his power ?
  • A. 337.5ms
  • B. 387.5W
  • C. 360W
  • D. 360J
Correct Answer: Option C - Given, mass of boy, m = 50 kg h = 45 x16 = 720 cm = 7.20 m t = 10 s, g = 10 m/s2 PE = mgh = 50 x 10 x 7.20 = 3600 J Power = PE / time = 3600 / 10 = 360 J/s = 360W
C. Given, mass of boy, m = 50 kg h = 45 x16 = 720 cm = 7.20 m t = 10 s, g = 10 m/s2 PE = mgh = 50 x 10 x 7.20 = 3600 J Power = PE / time = 3600 / 10 = 360 J/s = 360W

Explanations:

Given, mass of boy, m = 50 kg h = 45 x16 = 720 cm = 7.20 m t = 10 s, g = 10 m/s2 PE = mgh = 50 x 10 x 7.20 = 3600 J Power = PE / time = 3600 / 10 = 360 J/s = 360W