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

A body of mass 2 kg moves in a horizontal circular path of radius 5 m. At an instant, its speed is 2$$\sqrt5$$ m/s and is increasing at the rate of 3 m/s$$^2$$. The magnitude of force acting on the body at that instant is,

If a string, suspended from the ceiling is given a downward force F₁, its length becomes L₁. Its length is L₂, if the downward force is F₂. What is its actual length?