A particle moves with v=-3j+5i+6k ms-1under F=10i+10j+20k N. The power applied will be:
Correct answer: D. 140 Js-1
- A. 200 Js-1
- B. 170 Js-1
- C. 40 Js-1
- D. 140 Js-1
Explanation
Power = Force · Velocity Force · Velocity = (10i + 10j + 20k) · (-3j + 5i + 6k) (10i + 10j + 20k) · (-3j + 5i + 6k)= (10 * (-3) + 10 * 5 + 20 * 6)= (-30 + 50 + 120)= 140Therefore, the power applied to the particle is 140 J/s (joules per second).
Last updated
About Work and Energy
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.
Practise Work and Energy
748 free Work and Energy MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Physics questions like this
Physics is on 13 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.