When a man walks on a surface horizontally with constant velocity, work done by _.
Correct answer: D. All of these
- A. Friction is zero
- B. Contact force is zero
- C. Gravity is zero
- D. All of these
Explanation
Since mg and N are perpendicular to velocity v and s, work done by these force is zero. Since no relative sliding occurs during walking, static friction comes into play. Hence the point of application of static frictional force does not move. Therefore no work is done by frictional force. The man has to lose his body's (internal) energy E, hence performs work because W=ΔE
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
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.
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 questions
Work is a _.
A force of F = 1 + y N is acting in y direction, work done by this force to move the particle from y= 0 to y= 1m would be -------
Work done by friction force is always -------
If a horse pulls a cart, work done by horse is _.
An object is displaced from point A (2,3,4) m to point B (1,2,3) m under a constant force F=( 2i+3j+4k). Find the work done by this force in this process.
A constant force of 10N is applied in horizontal direction and distance travelled in the direction of force is 2m,then work done is _.