Question

The MKS unit of force is _____________.

Answer 1

Hint: We can find out the MKS unit of force by using the mathematical definition of force and putting the proper SI units of the physical quantities in the definition. Force on a body can be mathematically written as the product of the mass and the acceleration of the body.
Formula used:
The force $\overrightarrow{F}$ on a body is the product of the mass $m$ of the body and the acceleration $\overrightarrow{a}$ of the body produced due to that force.
$\overrightarrow{F}=m\overrightarrow{a}$

Complete step by step answer:
We can find out the MKS unit of force by writing its mathematical definition and writing the SI units of the physical quantities in the mathematical definition. The MKS unit is nothing but the SI system of units.
The force $\overrightarrow{F}$ on a body is the product of the mass $m$ of the body and the acceleration $\overrightarrow{a}$ of the body produced due to that force.
$\overrightarrow{F}=m\overrightarrow{a}$ --(1)
The SI unit of mass is kilogram $\left( kg \right)$.
The SI unit of acceleration is metre per second-squared $\left( m/{{s}^{2}} \right)$.
Hence, putting these two values in equation (1), we will get the SI (or MKS) unit of force as
$kg.m/{{s}^{2}}=kg.m.{{s}^{-2}}$
Hence, the SI (or MKS) unit of force is kilogram-metre per second-squared $\left( kg.m.{{s}^{-2}} \right)$. This unit is also known as Newton $\left( N \right)$.

Note: Students must also know of some other important units that are used commonly and that belong to other systems of units such as the CGS or FPS system. For example, the unit of force in the CGS system is dyne, which has the relation with the SI unit Newton as $1N={{10}^{5}}\text{dyne}$. Sometimes questions are set specifically giving the information values in a unit of a different system while the answer is required in the SI units. Hence, students should be thorough with the conversion of some important units of different systems into the SI units.