sir/mam please tell me why work has only magnitude but no direction with examples..

Asked by monisha binker | 4th Jan, 2014, 08:14: PM

Expert Answer:

Work = Force x Displacement
Hence work is the scalar product (dot product) of two vector quantities force and displacement.
Dot product of two vector quantities always gives a scalar quantity and scalar quantity has only magnitude not direction.
 
So work done is a scalar quantity. It does not have its own direction.
The direction of work is decided by the direction of force and displacement.
  • when the direction of force applied is in the direction of displacement then the work done is positive.
  • when the direction of force applied is opposite to the direction of displacement the work done is negative.
  • when the direction of force applied is perpendicular to the direction of displacement then work done is 0 because at 90 degree cos=0.
 

Answered by Komal Parmar | 5th Jan, 2014, 10:11: AM

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