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A uniform chain of L length and M mass, two third part of chain is on a frictionless table and one third part is vertically suspended, work done to pull the whole chain back on table is :

A uniform chain of L length and M mass, two third part of chain is on a frictionless table and one third part is vertically suspended, work done to pull the whole chain back on table is : Correct Answer MgL/18

The correct answer is option 1) i.e. MgL/18.

CONCEPT:

  • Work done is a measure of energy gained or lost by an object, when it is moved over a distance by an external force acting on it in the direction of displacement.
    • ​Work done (W.D) due to a force F to displace an object is given by:

W.D = F × displacement

  • ​The weight of an object is the force with which an object of considerable mass is being pulled by the force of gravity.
    • ​Weight of an object: W = m × g

Where m is the mass of the object and g is the acceleration due to gravity.

CALCULATION:

Given that:

Length of the chain = L

Mass of the chain = M

Important Points

  • The center of gravity of an object is the point at which weight is assumed to be concentrated. This is the average location of the weight of an object such that the object remains stable for this location of weight as well.
    • ​The centre of gravity for a few figures are as follows: 

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