What is the difference between Speed and Velocity? How are they related?
♦ Speed is scalar, so it changes due to magnitude only. Velocity is vector, so it changes due to change of both magnitude and direction. ♦ Speed is distance / time, so it can never be zero, as total length of paths covered ( distance) is never zero. But velocity, displacement / time, can be zero, as displacement can be zero when a particle returns to its initial position. ♦ When speed is uniform, velocity may or may not be uniform, as velocity alters with both magnitude and direction. However, when velocity is uniform, speed has to be uniform, as speed is the magnitude of velocity. Example: A body is speed 4 m/s. But it may move 4 m/s north, then 4 m/s east, then west, etc. So, although speed remains constant, velocity changes as direction changes. But, when a body moves with uniform velocity, say 6 m/s northward, then speed, magnitude of velocity, is 6 m/s, and so, it remains equal over the whole journey. ♦Again, speed, having no direction, can be added or subtracted algebraically. Bu
