Work done by friction force is always -------
Correct answer: D. Maybe positive, maybe negative
- A. Negative
- B. Positive
- C. Zero
- D. Maybe positive, maybe negative
Explanation
Option D is correct since students must note that generally friction is considered to be a dissipative force in nature that generally acts opposite to the direction of motion of an object and tries to decrease its kinetic energy. Hence, in general, friction does negative work. However, in some special cases friction can also do positive and zero work which might not seem so intuitive at first thought.
Last updated
About Work
Work is done when a force produces displacement, with its value determined by the component of force along the displacement. The topic covers positive, negative and zero work, work by variable forces from force-displacement graphs, and the connection between net work and change in kinetic energy.
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.
Related questions
A 1.75 m tall weight-lifter raises a weight of mass 50 kg to a height of 0.5 m above its head. How much work is being done by it? (g = 10 ms-2)
A 10 N force moves a body around a circular path of radius 50 cm. What is work done in completing one revolution?
A 10N force moves a body around a circular path of radius 50 cm. What is work done completing one revolution?
A 4kg eagle picks up a 75g snake and raises it 2.5 m from the ground to a branch. What is the workdone by the eagle on the snake? (g=10m/s2)
A 50kg man with a 20kg load on his head climbs up 20 steps of 0.25m height each. The work done in climbing is?