question_answer

For a particle in one dimensional motion, the instantaneous speed is always equal to the magnitude of instantaneous velocity. Why?

Answer:

                The rate of change of acceleration with time of a body is not important to mechanics. It is because, the basic laws of motion only involve acceleration, whereas as the quantity; rate of change of acceleration is not required at all. Newton also discovered that to understand and explain motion of a body, it is required to understand the rate of change of position (i.e. velocity) and rate of change of velocity (i.e. acceleration) and not the rate of change of acceleration of the body.