$A$ cube has numerically equal volume and surface area. The volume of such a cube is ........... $units$.

The unit $J \cdot s^2$ corresponds to which physical quantity?

Just as precise measurements are necessary in science,it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain,try to get an upper bound on the quantity):
$(a)$ The total mass of rain-bearing clouds over India during the Monsoon.
$(b)$ The mass of an elephant.
$(c)$ The wind speed during a storm.
$(d)$ The number of strands of hair on your head.
$(e)$ The number of air molecules in your classroom.

Consider the following statements:
$(A)$ Any physical quantity can have more than one unit.
$(B)$ Any physical quantity has only one dimensional formula.
$(C)$ More than one physical quantity may have the same dimension.
$(D)$ We can add and subtract only those expressions that have the same dimension.
The number of correct statements is:

Pressure exerted by a gas is found to be $50\, N/m^2$. What is the value of this pressure in the $CGS$ system?

Which of the following pairs does not have the same dimensions?