5) If a body of mass of 2 kg is raised vertically through 2m, then the work done will be: (Work, Power & Energy, Work Done by Constant Force and Variable forces)
Correct answer: C. 39.2 J
- A. 38.2 J
- B. 392j
- C. 39.2 J
- D. 3.92 J
Explanation
Reasoning: Work done (W) = Fd cos θ, where F is the force, d is the displacement, and θ is the angle between them. In this case, F = mg (weight of the body), d = 2 m (vertical distance), θ = 0° (force and displacement in the same direction), and g ≈ 9.81 m/s² (acceleration due to gravity). Therefore, W = (2 kg * 9.81 m/s²) * 2 m ≈ 39.2 J.Incorrect Options:(a) This is slightly off due to rounding errors in calculations.(b) This is a significant overestimation. It might be due to misinterpreting the units or miscalculating the force involved.(d) This is a substantial underestimation. It could be caused by confusion regarding the weight of the body or neglecting the gravitational acceleration value.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
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.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Work and Energy questions
Which of the following types of force does no work on the particle when it acts on it? (
When a force is perpendicular to the direction of motion of the body, then work done on the body is:
A field in which the work done in moving a body in a closed path is zero is called:
7. Rate of Average and Instantaneous Power is: (Work, Power & Energy, power and energy)
9. Proton, electron, neutron, and alpha particles have the same momentum. Which of them has the highest kinetic energy (KE)?(Work, Power & Energy, law of conservation of energy)
10. The power output of a lamp is 6W. How much energy does the lamp give out in 2 minutes? (Work, Power & Energy,power and energy)