| Assertion (A): | In an elastic collision of two billiard balls, the total kinetic energy is conserved during the short time of collision of the balls (i.e. when they are in contact). |
| Reason (R): | Energy spent against friction does not follow the law of conservation of energy. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
| Assertion (A): | In an elastic collision between two bodies, the energy of each body is conserved. |
| Reason (R): | The total energy of an isolated system is conserved. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | (A) is false but (R) is true. |
| Assertion (A): | Frictional forces are conservative in nature. |
| Reason (R): | A potential energy function can be associated with frictional forces. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| Assertion (A): | Work is the transfer of energy to or from an object due to a force acting on it. |
| Reason (R): | When energy is transferred to the object, the work done is positive; and when energy is transferred from the object, the work done is negative. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| Assertion (A): | For a closed isolated system during a collision, the linear momentum of each colliding body may change but the total linear momentum of the system cannot change, whether the collision is elastic or inelastic. |
| Reason (R): | Total mechanical energy is conserved, in an elastic collision. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| Assertion (A): | Power developed by the tension in the wire during vertical circular motion is always zero. |
| Reason (R): | Tension in the wire is equal to the centripetal force acting on the body under vertical circular motion. |
| 1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
| 3. | (A) is true but (R) is false. |
| 4. | Both (A) and (R) are false. |
| Assertion (A): | If a man is walking on a rough road, the work done by the frictional force is positive. |
| Reason (R): | Frictional force acts in the direction of the motion of the man. |
| 1. | Both assertion & reason are true and the reason is the correct explanation of the assertion. |
| 2. | Both assertion & reason are true but the reason is not the correct explanation of the assertion. |
| 3. | Assertion is a true statement but the reason is false. |
| 4. | Assertion is false but the reason is true. |
| Assertion (A): | Work done in uniform circular motion is zero. |
| Reason (R): | Force is always directed along displacement. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| Assertion (A): | Centripetal force does no work. |
| Reason (R): | Force and displacement are perpendicular to each other. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
| Assertion (A): | No work is done when an electron completes a circular orbit around the nucleus of an atom. |
| Reason (R): | Work done by a centripetal force is always zero. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |