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ashna
 3 years ago
Is it necessary that work done in the motion of a body over a closed loop is 0 for every force in nature ? why ?
ashna
 3 years ago
Is it necessary that work done in the motion of a body over a closed loop is 0 for every force in nature ? why ?

This Question is Closed

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2no...it's not true for every force in nature

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2take the example of work done by friction force.

ashna
 3 years ago
Best ResponseYou've already chosen the best response.0can you first explain the question ? :)

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2there are several forces in the nature..name them...whatever u know.

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2like electric force, magnetic force, spring force, friction force, gravitational force...

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2and these are all the closed loops

ashna
 3 years ago
Best ResponseYou've already chosen the best response.0i have to keep refreshing OS as its goin down , so my replays may seem late n am sry for that ! okay understood.

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2now suppose there is a ball situated at point A near the earth

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2and the ball is taken from point A to B to C to D to A..that is ball has been moved on a closed loop during this motion

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2earth is exerting force mg on the ball...so tell me work done by this gravitational force if ball moves from point A to B...use work done= force* displacement * cos(theta)

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2look for the angle between the force and the displacement

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2yes..so work done by gravitational force( A to B)=0

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2our objective is the work done by the gravitational force on the ball so now we come to B to C

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2ball is moving from B to C again work done by the gravitational force = force*( displacement) *cos(theta) theta=?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2there are two vectors..force (mg, vertically downward) and displacement( B to C)..so think carefully for angle between them.

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2displacement ( B to C) is vertically upward.

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2does it make sense for visualizing the angle between two vectors pictorially?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2so now we come to B to Cdw:1348897603389:dw

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2force is vertically downward and displacement is vertically upward so angle between them is......?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2yes...right..:) so work done by the gravitational force = force*( displacement) *cos(theta) = mg * h * (1) =mgh suppose BC=h

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2now work done by gravitational force (C to D)= 0 does it make sense?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2now we come to work done by the gravitational force on the ball (D to A) tell me how much it'll be?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2just look for angle between gravitational force and displacement when ball moves from D to A

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2so work done by the gravitational force on the ball (D to A)= mg* h* cos(0)= mgh BC=DA=h

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2so our objective has been completed...I mean...we have calculated...work done by gravitational force on the ball when the ball moved on a closed loop.

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2so total work done= W(A>B) + W(B>c) + W(C>D) + W(D>A) =0 + (mgh) + 0 + mgh =0

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2so work done by gravitational force in the motion of a body over a closed loop is 0.

ashna
 3 years ago
Best ResponseYou've already chosen the best response.0okay understood , and why is this not the same for every force in nature ?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2but we took a rectangular loop for a closed loop..one can show this for any arbitrarydw:1348898826574:dw closed loop

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2but it's not true for every force in nature...e.g. friction force

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2so we classify the forces into two type if work done by the force over a closed loop is zero then conservative force otherwise nonconservative force

ashna
 3 years ago
Best ResponseYou've already chosen the best response.0i don't understand , why not for frictional force ?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2yes...I am coming there

akash123
 3 years ago
Best ResponseYou've already chosen the best response.21st have a look...why not zero?dw:1348899134273:dw

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2suppose there is a block of mass m moves on a rectangular loop, and the loop is kept horizontally on the earth

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2do u agree that work done by the friction force on the block will be negative in each segment(AB, BC,CD,DA) of this loop?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2because during motion, angle between friction force and displacement will be 180'

ashna
 3 years ago
Best ResponseYou've already chosen the best response.0am sorry but i did not understand the last part !

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2which one...do u agree that work done by the friction force on the block will be negative in each segment(AB, BC,CD,DA) of this loop?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2ok...1st we'll see the work done by the friction force on the block,when it moves from A to B again work done= force*( displacement)* cos(theta) theta=?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2see..if block moves from A to B then displacement of block =AB...right?

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2direction of displacement is to the right and the direction of friction force is to the left

akash123
 3 years ago
Best ResponseYou've already chosen the best response.2so again there are two vectors friction force and displacement...look for the angle between them carfully

sam291
 3 years ago
Best ResponseYou've already chosen the best response.1But when it moves from C to D the direction of the force vector is opposite from the direction from A to B, so it will still add up to zero going around the loop. Am I wrong?

kappa007
 3 years ago
Best ResponseYou've already chosen the best response.1Forces in nature can be either conservative or nonconservative. Work done in a closed loop by a conservative force is always 0 .
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