The net external torque on a system of particles about an axis is zero. Which of the following are compatible with it?

In each of the following questions, a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements, mark the correct answer as-

Assertion (A): If a particle moves with a constant velocity then angular momentum of this particle about any point remains constant.

Reason (R): Angular momentum has the units of Planck's constant.

Codes:

In each of the following questions, a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements, mark the correct answer as-

Assertion (A): When a ball collides elastically with a floor, it rebounds with the same velocity as with it strikes.

Reason (R): Momentum of earth and ball system remains constant.

Codes:

In each of the following questions, a statement of Assertion is given followed by a corresponding statement of Reason just below it. Of the statements, mark the correct answer as-

Assertion (A): A small force can affect on same as large force.

Reason (R): The moment of a force is the product of force and its perpendicular distance from the axis of rotation.

Codes:

Consider the following statements:

I. A body having constant linear velocity may have some angular speed with respect to a point.

II. A force passing through the centre of rotation can produce moment to a body.

III. Torque has the SI unit N-m.

IV. Centre of gravity is point where entire mass of the body is assumed to be concentrated.

Which one of the following options are correct?

If ${\mathrm{I}}_{\mathrm{A}}$ and ${\mathrm{I}}_{\mathrm{B}}$ are the moments of inertia of a body about two axes $\mathrm{A}$ and $\mathrm{B}$ respectively. The axis $\mathrm{A}$ passes through the centre of mass of the body but $\mathrm{B}$ does not. Consider the following given below

I. ${\mathrm{I}}_{\mathrm{A}}<{\mathrm{I}}_{\mathrm{B}}$.

II. If ${\mathrm{I}}_{\mathrm{A}}<{\mathrm{I}}_{\mathrm{B}}$, the axes are parallel.

III. If the axes are parallel, ${\mathrm{I}}_{\mathrm{A}}<{\mathrm{I}}_{\mathrm{B}}$.

IV. If the axes are not parallel, ${\mathrm{I}}_{\mathrm{A}}\ge {\mathrm{I}}_{\mathrm{B}}$.

Which one of the following options is/are correct?

The elastic potential energy of a body is:

I. Work done by the external force against the restoring force.

II. Work done against the external force by the deforming force.

III. The sum of work done by the external force and the deforming force.

Which one option is true?

Consider the following statements:

I. The SI unit of Young's modulus of elasticity is ${\mathrm{Nm}}^{-2}$ or pascal.

II. Young's modulus is involved in solids only.

III. The SI unit of Bulk modulus of elasticity is ${\mathrm{Nm}}^{-2}$ or pascal.

IV. Bulk modulus is involved in solids, liquids and gases.

Which of the statements given above are correct?