Question

Pascal is the unit for
A. Pressure
B. Thrust
C. Buoyant force
D. None of these

Answer 1

Hint: One Pascal is Newton per meter squared i.e. ${N}/{{m}^{2}}$ or Kilogram per meter second squared i.e. ${kg}/{{ms}^{2}}$. Write the general formulas for pressure, thrust and buoyant force in terms of fundamental quantities. Substitute the S.I. units of these fundamental quantities and find whether the units of pressure, thrust or buoyant match the units of Pascal i.e. ${N}/{{m}^{2}}$ or ${kg}/{{ms}^{2}}$.
Formula used:
$Pressure= \dfrac {Force} {Area}$

Complete answer:
We know, one pascal is given by,
$1 Pascal = \dfrac {N}{{m}^{2}}$ ...(1)
Pressure is exerted when one Newton meter force is applied over an area of one square meter. So, the general formula for Pressure can be given by,
$Pressure= \dfrac {Force} {Area}$
Unit of force is Newton i.e. N while that area is meter squared i.e. ${m}^{2}$.
Thus, unit of pressure is $\dfrac {N}{{m}^{2}}$ ...(2)
From the equation. (1) and (2) we get,
The unit of pressure is Pascal.
Thrust is a force which is formed as a result of Newton's action-reaction pair. So, it will have the same unit of force. Thus, the unit of thrust is Newton.
Buoyant force is the same as thrust. So, it will also have the unit of force. Thus, its unit is Newton.
Hence, the Pascal is the unit for Pressure.

So, the correct answer is option A i.e. Pressure.

Note:
Students must remember that there are many units of pressure available such as Pascal, kilogram per meter second squared, Newton per meter squared, atmospheric pressure, bar, etc. But the most common units are atm i.e. atmospheric pressure and Pa i.e. Pascal. Pascal is used to perform mathematical calculations whereas atmospheric pressure is used for measuring atmospheric pressure at a given place.