Dimensions of a physical quantity are the powers to which the fundamental quantities must be raised.

We know that velocity **= displacement/time** = [L]/[T]

= [M°L^{1} T^{-1}]

where [M]. [L] and [I] are the dimensions of the fundamental quantities mass, length and time respectively.

Therefore velocity has zero dimension in mass, one dimension in length and -1 dimension in time. Thus the dimensional formula for velocity is [M^{0} L^{1} T^{-1}] or simply [LT^{-1}].The dimensions of fundamental quantifies are given in Table 1 and the dimensions of some derived quantities are given in Table 2.

**Table: dimensions of fundamental quantifies**

Table: the dimensions of some derived quantities