Q : Why do we use multi-stage rocket for launching a satellite ?
Sol. An artificial satellite is launched with the help of a multistage rocket . When the rocket is fired , the fuel of first stage rocket starts burning . This makes the rocket to reach the desired height with a definite speed .Now the first stage is detached itself from the remaining rocket and the fuel of second rocket starts burning . This will make the desired direction of rocket and will increase the height as well as the speed of rocket .When the fuel of second stage rocket is burnt completely , this stage is also separated from the remaining rocket . Now the fuel of last stage rocket starts burning . This will give the desired height and speed of the rocket .
When desired height is attained , the body placed at the nose of rocket is projected horizontally with the desired speed by automatic mechanical arrangement . (All these calculation are done in advance ) . Now the body will start orbiting around the earth with a definite period and becomes a satellite of earth .