## Efuchs 2 years ago Does time effect the work done?

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1. Taufique

work done=force * displacement*cos(theta) ..so workdone only depends on force vector and displacement vector ..it does not depends on time..but power depends on time because power is the workdone per unit time..

2. Akwasi07

But F=MA and A depends on time so why is it that time does not affect work done

3. richyw

work is given by the line integral $\int_C\mathbf{F}\cdot d\mathbf{x}=\int_{t_1}^{t_2}\mathbf{F}\cdot \mathbf{v}\,dt$where v is the velocity. So yeah the work done "depends" on time. In fact the time derivative of work is power

4. kr7210

there is two types of forces, one is velocity dependent and other one is velocity independent forces, so richyw is talking about first type and taufique is talking about second type........

5. Taufique

1. |dw:1357679432683:dw| 2.|dw:1357679632403:dw|

6. Taufique

In both case, the body is in rest at t=0 sec..but in both case if we calculate the work done then we will get same work done as 500 J..but here time is taken by a machine (Fext=10N) is different .. Now...if the work done depends on the time..then work done by the machine should be different in both case but here it is same in both case..so we can say that work done depends only external force applied by a machine and the initial position and final position of a body..

7. Taufique

work done by a system is the total change in energy of a system .$\ W=\Delta K.E$ or, $\ W =\Delta P.E$