Unit Conversion Help: A Simple Way to Make Sense of Confusing Conversions

[EvanVi]

i know this is a basic question but i need some assistance abut unit conversions. i want to know how to convert something like, say, 120km/hr to m/s but the way my teacher explains it is too confusing. i just want to know is there a simpler way to convert somthing like that easliy?

 

[Mindscrape]

You want to use dimensional analysis. The basic idea behind dimensional analysis is that you use equalities until you get the units you want. Let's take your example then

1km = 1000m

so divide by either 1000m or 1km depending on the situation, so you get an equality of 1. In this case we want kilometers on the bottom (denominator) so it cancels the kilometers up top (numerator).

1000m/1km = 1

so now we go the kilometer per hour equation and multiply it by 1 i.e. our equality

[tex]1\frac{km}{h} * \frac{1000m}{1km} = \frac{1000m}{h}[/tex]

Then you just continue on down the line

[tex]1\frac{km}{h} * \frac{1000m}{km} * \frac{1h}{60min} * \frac{1min}{60s} = \frac{1000 m}{3600s}[/tex]

Make sense?

EDIT:
There are probably a lot of threads like this that can give you some examples, but I know of another because I thought it was kind of cool what the guy was looking for once I understood his question.

https://www.physicsforums.com/showthread.php?t=177566&highlight=dimensional+analysis

 

[ogb p]

I understand that unit conversions can be confusing and overwhelming at times. However, it is an important skill to have in order to accurately interpret and communicate scientific data. Fortunately, there are some simple tricks and techniques that can make unit conversions easier to understand.

One helpful tip is to use the factor-label method, also known as dimensional analysis. This involves setting up a conversion equation with the given unit and the desired unit, and then canceling out the units until you are left with the desired unit. For example, to convert 120 km/hr to m/s, you would set up the equation as follows:

120 km/hr x (1000 m/1 km) x (1 hr/3600 s) = 33.33 m/s

Notice how the units cancel out, leaving you with m/s, the desired unit. This method can be applied to any type of unit conversion, making it a useful tool to have.

Another helpful tip is to understand the prefixes used in the metric system. For example, kilo (k) represents 1000, while milli (m) represents 0.001. Knowing these prefixes can make it easier to convert between units such as kilometers and meters.

In addition, there are many online resources and conversion calculators that can assist with unit conversions. These can be useful for double-checking your work or if you are unsure of the conversion factor.

In conclusion, while unit conversions may seem daunting at first, with practice and the use of helpful techniques, they can become easier to understand. As a scientist, it is important to have a strong understanding of unit conversions in order to accurately interpret and communicate scientific data.