Earphone definition, a sound receiver that fits in or over the ear, as of a radio or telephone. See more.
Answer Wiki. If a rocket went straight up, it would either continue in that direction and leave Earth, or it would fall back down, depending on its velocity. Most rockets intend to enter orbit, which is an elliptical trajectory, and it's much more efficient to arc into this trajectory than to go straight up and then accelerate laterally.
Have you noticed what happens if you let the air out of a balloon? The air goes one way and the balloon moves in the opposite direction. Rockets work in much the same way. Exhaust gases coming out of the engine nozzle at high speed push the rocket forward. Most modern launchers, such as Europeâs Ariane 5, are very complicated and weigh hundreds of tonnes at liftoff. Most of this weight is fuel, such as liquid hydrogen and liquid oxygen. Rockets need so much fuel in order to overcome Earthâs gravity. Only when they reach a speed of 28 000 km/h are they travelling fast enough to enter orbit.