A particle of mass \(4M\) kg at rest splits into two particles of mass \(M\) and \(3M.\) The ratio of the kinetic energies of mass \(M\) and \(3M\) would be:
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): | 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. \(\dfrac{4}{9}\)