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Question: Now work is done by a force if the body (a) Moves is direction of force. (b) does not move. (c...

Now work is done by a force if the body
(a) Moves is direction of force.
(b) does not move.
(c) Moves in opposite direction
(d) None of these

Explanation

Solution

Hint : Work in physics, measure of energy transfer that occurs when an object is moved over a distance by an external force at least part of which is applied in the direction of the displacement.
Work is equal to the force FF line the distance d,d,
w=Fdw=Fd
If the force is being exerted at an angle θ\theta to the displacement.
The work done is W=FdcosθW=Fd\cos \theta
Work done on a body is accomplished not only by a displacement of the body as a whole from one place to another but also by compression a gas, by rotating a shaft and even by causing invisible motion of the particles within a body by an external magnetic force.
Where W=W= word done
F=F= force
d=d= displacement
θ=\theta = angle.

Complete Step By Step Answer:
Work done by a constant force: When a force acts or an object over a distance, it is said to have done work on the object physically, the work done on an object is the change in kinetic energy that object experiences. We will rigorously prove both of these claims.
SI unit of work is the newton meter or Joule (J)(J)
We have claimed that work is the change in kinetic energy of an object and that it is also equal to the force time, distance. The unit of these two should agree, kinetic energy and all forms of energy have unit of joule (J)(J) likewise, force has unit of newton (N)(N) and distance has unit of meter (m).(m).
If the two statements are equivalent they should be equivalent to one another.
N.m=kgms2=kgm2s2=I\therefore N.m=kg\dfrac{m}{{{s}^{2}}}=kg\dfrac{{{m}^{2}}}{{{s}^{2}}}=I
In conclusion, the answer is option (b).

Note :
The principle of work and kinetic energy (also known as the work energy theorem) states that the work done by the sum of all forces acting on a particle equals the change in the kinetic energy of the particles. In this question the work is defined by the movement of the object/body.