Question #4e99f

1 Answer
Matt
May 18, 2016

This is probably relating to questions where the force is applied at an angle to the direction in which an object is moving

Explanation:

I am second guessing the problem here but I assume you have seen work done equations as
#W=FS#
and also
#W=FS*costheta#

The definition of work done is:

work done = force x distance moved in direction of force

If this relates to a problem along the following lines, such as "what is the work done on the object if the weight is pulled along in the horizontal direction by a distance S?"
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Then in the above, the force can be resolved into a horizontal component (#Fcostheta#) and a vertical component (#Fsintheta#).

Work done in the vertical direction is nil (no distance is travelled in the vertical direction) whereas work done in the horizontal direction would be #W=FS*costheta#

A more technically correct definition of work done is that it equals the dot product of two vectors, force and displacement. Hence:
#W=vecF*vecS#
The solution to this is
#W=FS*costheta# where F and S are the magnitudes of the force and displacement (identical to the above)

Does this help?

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