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°L1 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 [M0 L1 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