| 1. | \(M=m\) | 2. | \(M=2m\) |
| 3. | \(M\ll m\) | 4. | \(M\gg m\) |
| 1. | \(3:1\) | 2. | \(1:4\) |
| 3. | \(1:1\) | 4. | \(1:3\) |
| Assertion (A): | When a firecracker (rocket) explodes in mid-air, its fragments fly in such a way that they continue moving in the same path, which the firecracker would have followed, had it not exploded. |
| Reason (R): | The explosion of cracker (rocket) occurs due to internal forces only and no external force acts for this explosion. |
| 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. |
Body \(\mathrm{A}\) of mass \(4m\) moving with speed \(u\) collides with another body \(\mathrm{B}\) of mass \(2m\) at rest. The collision is head-on and elastic in nature. After the collision, the fraction of energy lost by the colliding body \(\mathrm{A}\) is:
| 1. | \(\dfrac{5}{9}\) | 2. | \(\dfrac{1}{9}\) |
| 3. | \(\dfrac{8}{9}\) | 4. | \(\dfrac{4}{9}\) |