Monday, December 14, 2015

Maximum and Minimum Work done by applied Force

Work is said to be done when applied force is able to produce some displacement. The magnitude of work done is depends on the applied force, displacement of the body and the direction of applied force with respect to displacement.

If the applied force is along the same direction of force, then the entire force causes displacement and hence work done in that case is maximum. It is simply because COS 0 is equal to ONE.

If the applied force is at a certain angle, then only a component of force produces displacement and hence the work done in this case is not maximum.

If the applied force is perpendicular to the displacement of the body, the actual applied force is not causing any displacement and hence work done by the applied force is equal to zero.

If a railway porter is carrying a suitcase on smooth horizontal surface, and his displacement on the horizontal surface itself, weight acts in the downward direction and displacement is perpendicular to the weight. Hence work done is zero against the weight.

If the applied force is in one direction and the displacement of the body is in the opposite direction, then work done is minimum as COS 180 is equal to minus one. This is the minimum possible work done and work  done is maximum when force and displacement are in the same direction.

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  1. how to measure work done by siphon when it empty the given volume and rate of flow is given and length of tube is given and height is given so which formula define the work done per second please give me an idea about it

  2. Work done can be expressed as the product of constant pressure and the change in the volume of the system. Pressure can be expressed as the product of height of liquid level,density of liquid and acceleration due to gravity.Thus we get the work done and you need the work done per unit time so we need to divide the work done with time. Any way volume per time is given to us. Thus multiplying the pressure with volume per unit time gives us the work done per unit time. Further comments are welcome and all the best Anil.