Main Question or Discussion Point
I'm not sure how the speed of light squared makes any sense? What is MASS X C2?
I'd just like to expand on this so the OP doesn't get confused:Consider the units of mc2:
[kg]·[m/s]2 = kg·m2/s2 = J (joules) which is a unit of energy.
The c2 is basically a unit-conversion factor between kg and J.
Well, that's where the problem is, they are similar but not the same thing.Yes, 42=4*4=16. Similarly, c2=c*c.
Correct, I chose to leave the units out of it however, just to explain the concept of exponentiation. I mentioned dimensional analysis in an earlier post.Well, that's where the problem is, they are similar but not the same thing.
Take number 4. Then 4*4=16, which is a number 4 times higher.
Take c, which is about 3*108 m/s. Then c2=c*c=9*1016 m2/s2. Then c2 is not simply 3*108 times higher than c. It is 3*108 m/s higher than c. Their different physical dimensions (or units) mean that c and c2 are not the same kind of quantity, like both were numbers. They are different kinds of physical quantities and they cannot be compared.
It's just like one cannot say that 16 geese is 4 times more than 4 houses.
Would it be wrong to say: "I have four times as many geese as chickens"?It's just like one cannot say that 16 geese is 4 times more than 4 houses.
You're missing my point, though. We all know when we see a specific example what makes sense and what doesn't, but the general rules seem to be more complicated than at first sight.Nope. In your example you are counting animals. If you were measuring your livestock, it would be different. That's why in estimating livestock cows and sheep don't count the same.
A metre is one-dimensional. Squaring it makes it 2-dimensional. It is no longer a metre but a square metre. If you have 4 rows of 4 square metres you also have 16 square metres just like you have 16 marbles. Study dimensional analysis as mentioned above and all will become clear.Would it be wrong to say: "I have four times as many geese as chickens"?
The relationship between numbers and physical quantities is, perhaps, surprisingly subtle.
For example: if you have 4 rows of 4 marbles, then you have 16 marbles, not 16 square marbles. Yet, 4m by 4m is 16##m^2##.
Also, mass x velocity = momentum, but mass + velocity makes no sense.
Yet: 1 goose + 1 chicken makes sense, whereas, what would be meant by goose x chicken is not so clear!
It's simply a conversion factor to get from one unit of measurement to another. Kind of like how lbs = 0.453592*kg. I say "kind of" because I'm sure there are some subtle differences that I'm not familiar with.I'm not sure how the speed of light squared makes any sense? What is MASS X C2?
When you double a speed you get another speed. When you square a speed you don't get another speed.I see it as something like 22=4 and 42=16. So I don't get how we "double" the speed of light?