As dimensions do not depend on the magnitude of the quantity, therefore both vi and vf have same dimensions = [ms-1] = [LT-1] …. (1)
Dimensions of acceleration, a = ms-2 = [LT-2] … (2)
Dimensions of distance, S = [L] (3)
Dimensions of time, t = [T] (4)
Now put the values of the dimensions of velocity, acceleration and time in equation (a).
[LT-1] = [LT-1] + [LT-2][T] = [LT-1] + [LT-2T] = [LT-1] + [LT-1]
⇒[LT-1] = 2[LT-1].
Since 2 is dimensionless number, therefore, [LT-1] = [LT-1]. Therefore, the equation is dimensionally correct.
- Put the respective dimensions from the above four equations, we have [L] = [LT-1][T] + ½ [LT-2][T2] ⇒ [L] = [LT-1T] + ½ [LT-2T2] = [LT-1+1] + ½ [LT-2+2] = [LT0] + ½ [LT0] = 3/2 [L]. And since 3/2 is dimensionless number, therefore, the equation becomes [L] = [L]. Thus the equation is dimensionally correct.