Question

The total work done on a particle is equal to the change in its kinetic energy. This statement is an application in
(A) Always
(B) Only if the force acting on the body is conservative.
(C) Only in the inertia frame.
(D) Only if no external force is acting.

Answer 1

Hint: To solve this type of question we use the work-energy theorem which gives the relation between work done and change in kinetic energy. The energy of mass in motion is known as Kinetic energy. Energy does not depend on the direction as it is a scalar quantity. It will always be positive.

Complete step by step answer:
According to the work-energy theorem, the total work done by all forces acting on a particle is always equated to the change in the kinetic energy of the particle. Here, acting forces can be conservative or non-conservative.
The mathematically work-energy theorem is given below.
$W_{net}=\mathrm{\Delta }KE=K{E}_{final}-K{E}_{initial}$
Therefore, the work-energy theorem is valid for all types of forces acting on the body.

$\therefore$ The total work done on a particle is equal to the change in its kinetic energy. This statement is always correct. Hence, option (A) is the correct option.

Additional information:
According to Archimedes’ principle, when a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it. The loss of weight of the body is equal to the resultant upthrust. The resultant upthrust on a body is called buoyancy. The resultant upthrust acting on a body is equal to the weight of the displaced liquid.
For a body to float in equilibrium on the surface of a liquid, the following two conditions must be satisfied.

Note:
In the case of non-conservative forces, the energy dissipated gets converted into heat energy in this way the law of energy is satisfied.
In the case of conservative forces work done is independent of the path taken. It only depends on the initial position and final position.
Therefore, for a conservative force, if a particle moves in a closed path then the total work done will be zero.
The following formula is used to calculate Kinetic energy:
$KE=m{v}^2$, Where $m$ is the mass and $v$ is the velocity of the object in motion.
We should keep in mind that in the work-energy theorem work done is not of a single force, instead it is the total work done by all the forces working on the object.