- Dimensional analysis has no information on dimensionless constants.
- If a quantity is dependent on trigonometric or exponential functions, this method cannot be used.
- In some cases, it is difficult to guess the factors while deriving the relation connecting two or more physical quantities.
- This method cannot be used in an equation containing two or more variables with same dimensions.
- It cannot be used if the physical quantity is dependent on more than three unknown variables.
- This method cannot be used if the physical quantity contains more than one term, say sum or difference of two terms.
Solved problems
a) Convert a velocity of 48 kmh-1 into ms-1b) Convert an acceleration of 48 km min-2 into ms-1
a) v = 48kmh-11 km = 1000 m, 1h = 60 x 60 s

b) a = 48kmmin-2
1 km = 1000 m, 1min = 60 x 60 s

