Question

What is the S.I. base unit of mass?

Answer 1

Hint: This question is based upon the units and dimensions of different types of quantities and variables in general physics. We need to know what mass is, and sometimes we also confuse mass by weight. Both these quantities are different and have different units.

Complete answer:
The kilogram is the SI unit of mass (kg). The weight of a body in a particular reference frame is known in science and technology as the force that causes the body to accelerate at the same rate as the local acceleration of free fall in that reference frame.
A body's mass is a measurement of its inertial property, or the amount of matter it comprises. The force exerted on a body by gravity or the force required to support it is measured by its weight. On Earth, gravity accelerates a body downward at around 9.8 $$m/s^2$$. In the context of weights and measures, weight is often used as a synonym for mass. However, the SI unit of the quantity weight defined in this way (force) is the newton (N).

Note: The kilogram (kg) is the only SI base unit whose name and symbol contain a prefix for historical reasons. The SI prefix for 1000 or ${10}^3$ is "kilo." Prefix names and symbols are attached to the unit name "gram," and prefix symbols are attached to the unit symbol "g," to create names and symbols for decimal multiples and submultiples of the unit of mass.