Can someone please explain how to do this?

Question

vshiroky · Answer

attachment

vshiroky · Answer

@johnweldon1993

johnweldon1993 · Answer

Alright...well the tire is how big in diameter? *we are given the radius*

vshiroky · Answer

Do I square it?

vshiroky · Answer

I don't remember how to get Diameter

johnweldon1993 · Answer

No

$$\large \text{Diameter} = 2r$$

You just multipy the radius by 2 :)

vshiroky · Answer

Ok do D=50

johnweldon1993 · Answer

Correct....

Now....do you know already that 1 full rotation will = $\large 2\pi$?

vshiroky · Answer

Huh?

vshiroky · Answer

i do 2 time pie?

johnweldon1993 · Answer

1 full rotation...is equal to $\large 2\pi$

Look at the unit circle

|dw:1396890433743:dw|

when youu go fully around it...you go to 2pi

johnweldon1993 · Answer

Well not exactly...not here...so what we do here is just realize that 2pi = 1 rotation...okay?

But our tire is not just 1 in diameter....

1 rotation of our tire! will be

$$\large 50 \times 2\pi = 100\pi$$

vshiroky · Answer

@johnweldon1993

vshiroky · Answer

I still don't understand lol

vshiroky · Answer

Ok... my stuff just posted all out of order lol... so I don't do 2 times pie, then times 50? I don't know why pie mind F*** me

vshiroky · Answer

Where do you get the 100 pi

vshiroky · Answer

Ok...

vshiroky · Answer

All my stuff keeps showing up weird... on my end

johnweldon1993 · Answer

sorry openstudy just went off on me lol

vshiroky · Answer

I'm going to close this and open a new question

johnweldon1993 · Answer

Alright...so

1 rotation = 2pi

But our tire is 50 in diameter....

so to get the distance covered by 1 full rotation of the tire...we do

$$\large 50 \times 2\pi$$ which is where I got the 100pi