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.
How fast can conventional rockets go? Any rocket can achieve a very high speed if it accelerates for a long time. A conventional rocket has a hard time doing this because a huge amount of fuel must be carried into space in order for this to happen. This may make the rocket too heavy to lift off.