Speed

Speed of an object is defined as the time rate of change of position of the object in any direction. It is measured by the distance travelled by the object in unit time in any direction. i.e.,

$ \displaystyle \text{Speed = }\dfrac{{\text{distance travelled}}}{{\text{time taken}}}$

Speed is a scalar quantity. It gives no idea about the direction of motion of the object. The speed of the object can be zero or positive but never negative. The unit of speed is cm/s in CGS system and m/s in MKS system or S.I. The dimensional formula of speed is $ \displaystyle \left[ {{{M}^{0}}{{L}^{1}}{{T}^{{-1}}}} \right]$.