Question

In the SI system, the unit of work is____________.

Answer 1

Hint: At first we need to know the definition of work done, what is work and how is it calculated. Then we have to find the unit of the values used in the formula for calculating work. So, from these units we could understand what is the unit of work.
Formula used:
$W=Fd\cos \theta $

Complete step by step answer:
We know that work is nothing but defined as the measure of the displacement of an object or a point. It is actually a mechanical manifestation of energy. Some common examples of force include riding a bike up to the hill.
Now, we will see how mathematically we represent the work done,
$W=Fd\cos \theta $.
Now, when we calculate work we get the resultant unit joule. One joule is defined as the work done by a force of one newton which is causing a displacement of one meter. In some cases N.m is also used to calculate work done but this unit is also used for torque so people might get confused from it that’s why the SI authority does not encourage the use of it.
So, according to the above information given we can say that, In SI system, the unit of work is Joule.

Additional Information:
There are some commonly used units of work which include erg in the CGS system, the newton meter, foot-pound, then kilowatt hour, litre-atmosphere.
We can say that work has the similar physical dimensions as heat has, therefore the measurement units such as therm, calorie and BTU are also used for measuring work done.

Note:
In the formula $W=Fd\cos \theta $, F is the force with which displacement is done, ‘d’ is the displacement. While solving the question students must remember the formula for work done and what is the definition of work.