In a new system of units, mass is measured in multiples of [tex]$10 \, \text{kg}$[/tex], length is measured in multiples of [tex]$1 \, \text{km}$[/tex], and time is measured in multiples of [tex]$100 \, \text{s}$[/tex]. The numerical value of 1 joule in the new system of units is:

(1) [tex]$10^{-1}$[/tex]
(2) [tex]$10^{-2}$[/tex]
(3) [tex]$10^{-3}$[/tex]
(4) 10



Answer :

To determine the numerical value of 1 joule in the new system of units, we must express the definition of 1 joule in terms of the new units of mass, length, and time.

First, let’s recall that the joule (J) in the SI system is defined as:

[tex]\[ 1 \, \text{J} = 1 \, \text{kg} \cdot \left(1 \, \text{m}\right)^2 \cdot \left(1 \, \text{s}^{-2}\right) \][/tex]

In the new system:
- Mass is measured in multiples of [tex]\(10 \, \text{kg}\)[/tex], so [tex]\(1 \text{ mass unit} = 10 \, \text{kg}\)[/tex].
- Length is measured in multiples of [tex]\(1 \, \text{km}\)[/tex] or [tex]\(1000 \, \text{m}\)[/tex], so [tex]\(1 \text{ length unit} = 1000 \, \text{m}\)[/tex].
- Time is measured in multiples of [tex]\(100 \, \text{s}\)[/tex], so [tex]\(1 \text{ time unit} = 100 \, \text{s}\)[/tex].

To convert 1 joule (J) into the new system of units, we substitute these new units into the joule’s definition. We have:

[tex]\[ 1 \, \text{J} = 1 \, (\text{new mass unit}) \left(\text{new length unit}\right)^2 \left(\text{new time unit}\right)^{-2} \][/tex]

Inserting the values given for new mass, new length, and new time:

[tex]\[ 1 \, \text{J} = 1 \times 10 \, \text{kg} \times \left(1000 \, \text{m}\right)^2 \times \left(100 \, \text{s}\right)^{-2} \][/tex]

Calculate the exponents:

[tex]\[ 1 \, \text{J} = 1 \times 10 \, \text{kg} \times 1000000 \, \text{m}^2 \times \left(100 \, \text{s}\right)^{-2} \][/tex]

Now, break it down:

[tex]\[ 1000000 \, \text{m}^2 \text{ is } 10^6 \, \text{m}^2 \][/tex]
[tex]\[ \left(100 \, \text{s}\right)^{-2} \text{ is } \left(10^2 \right)^{-2} = 10^{-4} \, \text{s}^{-2} \][/tex]

Thus:

[tex]\[ 1 \, \text{J} = 10 \times 10^6 \times 10^{-4} \][/tex]

Combine the factors of 10:

[tex]\[ 1 \, \text{J} = 10 \times 10^{6-4} \][/tex]
[tex]\[ 1 \, \text{J} = 10 \times 10^2 \][/tex]
[tex]\[ 1 \, \text{J} = 10 \times 100 \][/tex]
[tex]\[ 1 \, \text{J} = 1000 \][/tex]

Therefore, the numerical value of 1 joule in the new system of units is:

[tex]\[ \boxed{1000.0} \][/tex]

So, the correct answer is neither (1) [tex]\(10^{-1}\)[/tex], (2) [tex]\(10^{-2}\)[/tex], (3) [tex]\(10^{-3}\)[/tex], nor (4) 10, but rather [tex]\(1000.0\)[/tex]. It appears the question may have an oversight in the available options.

Other Questions