Question

State the S.I. unit of mass and weight.
$\begin{align}
  & \text{A}\text{. g and kg} \\
 & \text{B}\text{. kg and g} \\
 & \text{C}\text{. kg and N} \\
 & \text{D}\text{. N and kg} \\
\end{align}$

Answer 1

Hint: Mass is the total constituent present in a given volume. Mass is a basic fundamental quantity. Weight can be defined from newton law. Weight of an object is equal to the product of the mass of the object and acceleration of gravity. If the mass is under gravity then mass gets converted into weight.

Complete step-by-step answer:
The fundamental property of an object is the mass. A numerical measure of its inertia, a fundamental measure of the amount of matter in the object is the mass of an object. Definition of mass often seems confusing and in a circular way because it is such a fundamental quantity which is complicated and tough to define in terms of something else. Quantities in mechanical quantities can be defined in terms of mass, length and time. The most common symbol of mass is $m$. S.I. unit of mass is the kilogram. We all know that force is a product of mass and acceleration and newton is the unit of force, denoted as $N$.
Mathematically it is written as $N=mg$.
So weight can be written as $W=mg$.
The term $m$ which is given in the above formula is known as weight.
The weight of an object is defined as the force of gravity on the object.
Therefore the correct option is (C) .i.e S.I. unit of weight is the newton $(N)$.

Note: Students usually do not differentiate the difference between mass and weight. Mass is the constituent present in an object and weight applied at all the times, even when the object is not accelerating. Students usually try to memorize the SI units, but it is a wrong way to do these types of questions. Students should only memorize the basic formulas, and they should convert the given formula into basic units to dimensional formulas or S.I. units.