What is Work: Definition and 1000 Discussions

In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, it is often represented as the product of force and displacement. A force is said to do positive work if (when applied) it has a component in the direction of the displacement of the point of application. A force does negative work if it has a component opposite to the direction of the displacement at the point of application of the force.
For example, when a ball is held above the ground and then dropped, the work done by the gravitational force on the ball as it falls is equal to the weight of the ball (a force) multiplied by the distance to the ground (a displacement). When the force F is constant and the angle between the force and the displacement s is θ, then the work done is given by:




W
=
F
s
cos
⁡

θ



{\displaystyle W=Fs\cos {\theta }}
Work is a scalar quantity, so it has only magnitude and no direction. Work transfers energy from one place to another, or one form to another. The SI unit of work is the joule (J), the same unit as for energy.

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  1. S

    Is the work done by friction on a moving car's wheel positive or negative?

    The answer key is (b) but in my opinion it should be (d) because I think about work done by friction on wheel of car when the car moves. Let say the car moves to the right, then the wheel will rotate clockwise and the direction of friction acting on the wheel by the road will be to the right and...
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  3. L

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  4. L

    B Can Inductive Reasoning Explain the Movement of Strings on Spools and Bikes?

  5. resurgance2001

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  6. Trysse

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  8. bluesteels

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    u = (9*10^9)(1.61*10^-19)^2 * (1/[3*10^-15 ]- 1/[2*10^-10]) u = 7.68*10^-14 J but here the question. I have been taught that W= -U so shouldn't the answer be negative?? When i look up at the solution all other sources say that the W = U and therefore the answer is in postive.
  9. R

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  11. Ced

    Can You Help Solve This Generalized Work Problem with an Illustrative Image?

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  12. M

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  13. kara123

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  14. lonewolfx

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  15. H

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  16. P

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  19. rudransh verma

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  21. H

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  22. Iwanttolearnphysics

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  23. TheBigDig

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  24. Ugnius

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  29. Z

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  32. Dario56

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  33. J

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  34. A

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  35. M

    Can anyone please check/confirm my work on this proof?

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  36. docnet

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  37. C

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  41. Nick Tucker

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  42. M

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  43. T

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  46. M

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  48. K

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  49. R

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  50. ikihi

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