PA_M7_S2_T2_Converting
Units of Weight Transcript
Weight is another English unit that we often have to convert. Once again
you're going to see that the conversion factors have the reciprocal that
is useful when we're going from one unit to the next or back.
My basic conversions are going to be from pounds to ounces or ounces to
pounds, and tons to pounds or pounds to tons. Again we'll set it up in
the same way. If I am going from pounds to ounces, my conversion factor
will have the ounces on the top to 1 pound in the bottom so my pounds
will cancel. If, on the other hand, I'm going from ounces to pounds and I
have some number of ounces, then my conversion factor will be 1 pound to
16 ounces. Again I only need to know one of these conversion factors in
order to make use of it both directions as long as I keep track of the
fact that I want to cancel a unit that's on the top, the unit I start
with, with a unit on the bottom in my conversion factor.
Let's look at some examples of changing pounds to ounces and tons to
pounds. In the first case I have 2 1/2 pounds and I want to convert that
ounces.
I'm going to write my 2 1/2 as 2.5
because it makes things a little easier
to work with, and I use my abbreviation
for pounds. Since I'm converting from
pounds to ounces my conversion factor
needs to have the ounces on the top and
the pounds in the bottom. There are 16 ounces in 1 pound so this will be
my conversion factor. My pounds will cancel and I'm left with multiplying
2.5 times 16 to get my ounces, giving me 40 ounces as the equivalent of 2
1/2 pounds.
Let's look at the next one, 3.2 tons to pounds. I have 3.2 tons, I want
to go to pounds so that top value will be
in pounds and my bottom value will be in
tons. There are 2000 pounds per one ton,
the ton will cancel and I'm left with 3.2
times 2000 to give me my equivalent
measure in pounds.
Conversions of weight may also involve multiple conversion factors to get
from one point to the next.
Here is an example, I have 48,000 ounces and I want to know what that is
in tons. I don't have a direct conversion from ounces to tons, so what I
want to do is I want to convert these ounces into pounds. 1 pound is 16
ounces, so this is the first conversion factor because it's going to
allow me to cancel my ounces and what I'm going to get is that there are
3000 pounds represented by 48,000 ounces. Now I'm going to convert to
tons, One ton is 2000 pounds, my pounds will cancel, and I divide 3000 by
2000, and I get 1.5 tons.
So again I could have additional conversion steps, I just have to make
sure that I understand the relationships between everything and set them
up so that the appropriate units cancel.