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.
The laws are shown above, and the application of these laws to rockets is given on separate slides. Newton's first law states that every object remains at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force.