A shell of mass 10 kg is moving with a velocity of 10 ms^$$-$$1 when it blasts and forms two parts of mass 9 kg and 1 kg respectively. If the 1st mass is stationary, the velocity of the 2nd is

Force required to move a mass of 1 kg at rest on a horizontal rough plane ($$\mu$$ = 0.1 and g = 9.8 m/s²) is

A rocket of mass 100 kg burns 0.1 kg of fuel per sec. If the velocity of exhaust gas is 1 km/sec, then it lifts with an acceleration of

A bullet emerges from a barrel of length 1.2 m with a speed of 640 ms^$$-$$1. Assuming constant acceleration, the approximate time that it spends in the barrel after the gun is fired is