Question

SI unit of work is___________(watt, joule).

Answer 1

Hint: Convert the mathematical formula of work into basic units in the MKS system. Use the formula of work. Use the formula of force. Use an explicit unit. Consider all units quantity as one ex. 1 Kg, etc.

Complete Step-by-Step solution:
The International System of Units (SI) is the modern form of the metric system. It is the only system of measurement with official status in nearly every country in the world. It comprises a coherent system of units of measurement starting with seven base units.
Force (the unit of time with the symbol F),
Displacement (length, m),
Work is defined as work done by force of one newton through a displacement of one meter. The symbol for it is w or W. Mathematically it is represented as,
$W=F\times x$
Where:
W is the work
F is the force
x is the displacement
(To get the SI unit, we will break the formula of work into basics units.)
As we know, force is mass times acceleration where the acceleration unit is $meter/(second)^2$. The units of the area would be (meter) square.
$F=ma$
So SI unit work is
$W=\dfrac{Kg*{{m}^{2}}}{{{s}^{2}}}$
This is equal to one joule. So the SI unit of pressure is joule. Hence, the correct answer is Joule.

Additional Information:
Work is an SI unit of work in the MKS system, whereas erg is in the CGS units. Joule is equal to one newton-meter. One joule per second is watt.

Note: 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 formula or SI units.