What is the minimum escape velocity of the rocket to be launched into space?

(1) 5 Km/Sec.

(2) 6 Km/Sec.

(3) 11 Km/Sec.

(4) 15 Km/Sec.

**Answer: **(3) On the surface of the Earth, the escape velocity is about 11.2 kilometres per second (~6.96 mi/s), which is approximately 34 times the speed of sound (Mach 34) and several times the muzzle velocity of a rifle bullet (up to 1.7 km/s). However, at 9,000 km altitude in “space”, it is slightly less than 7.1 km/s. In physics, escape velocity is the speed at which the kinetic energy plus the gravitational potential energy of an object is zero. It is the speed needed to “break free” from a gravitational field without further propulsion. A rocket moving out of gravity well does not actually need to attain escape velocity to do so but could achieve the same result at any speed with a suitable mode of propulsion and sufficient fuel. Escape velocity only applies to ballistic trajectories.