Two identical balls A and B are moving with velocity and respectively. If they collide head on elastically, then their velocities after collision will be:
1.
2.
3.
4.
A particle projected with velocity 'u' makes an angle θ with respect to horizontal. Now it breaks in two identical parts at highest point of trajectory. If one part retraces its path, then velocity of the other part is:
1. 3u cos θ
2. 2u cos θ
3. u cos θ
4. u
A stationary particle explodes into two particles of masses m1 and m2 which move in opposite directions with velocities v1 and v2. The ratio of their kinetic energies E1/E2 is:
1. m2/m1
2. m1/m2
3. 1
4. m1v2/m2v1
A bomb of mass 30kg at rest explodes into two pieces of masses 18 kg and 12 kg. The velocity of 18kg mass is 6ms–1. The kinetic energy of the other mass is:
1. 524 J
2. 256 J
3. 486 J
4. 324 J