Question

In a practical unit, if the unit of mass becomes double and that of u becomes half, then 8 joules will be equal to _____ unit of work
A. 8
B. 4
C. 1
D. 10

Answer 1

Hint: For solving this question, you must know the units that are included in the unit of work. After that convert the units as given in the question and use it in the given value of work. You will get the answer after solving for the required conversion. In physics, by the application of force along a displacement, function is the energy transmitted to or from an object. It is also represented as the product of force and displacement in its simplest form as given below.

Formula Used:
$Work=Force\times Displacement=F\cdot s$

Complete step by step answer:
Now,
8 joules of work done can be expressed, as
Work = 8 joules = \[8kg{{m}^{2}}{{s}^{-2}}\]
where units are,
mass = kg
length = m
Time = s
Now,
Let the new units be KG, M and S
So,
According to the question,
KG = 2kg
And,
S = 2s​
And,
M = m
Work = \[8kg{{m}^{2}}{{s}^{-2}}\]
\[=8\left( KG/2 \right)\times {{M}^{2}}{{\left( 2S \right)}^{-2}}\]
\[=\dfrac{8}{8}\left( KG{{M}^{2}}{{S}^{-2}} \right)\]
\[=1~Joule\text{ }of\text{ }work.\]
So, In a practical unit, if the unit of mass becomes double and that of u becomes half, then 8 joules will be equal to 1 unit of work, i.e., Option – C

Note:
The current version of the metric system is the Foreign System of Units. In virtually every country in the world, it is the only method of measurement with official status. SI units help in maintaining the consistency all around the globe.