Can Somone Check

[eXg. TrueGift]

My work I'm not sure If I got it right, question is

A car tire has a radius of 36cm. A stone gets stuck in the tire. How many times will it hit the ground when the car travels 1km? Show your work!

So if you could, check my answers?

[s3lf]

Not quite, but you're on the right track.

First - I would convert to meters since your numbers will be easier to manage (and meters are SI units which are best to use for science).

So - your radius / diameter and circumference calculations are correct. However, in meters:

r = 0.36m
d = 0.72m

Therefore, C = pi x d = 3.14159265... x 0.72m. C = 2.26194671... m.

Now, 1 km = 1000 m.

At this point, you don't want to multiply C x distance. You want to know how many times your wheel will turn IN 1000 m. Right? So, divide.

1000 m / C = 1000 m / 2.26194671 m = 442.097 revolutions.

In this situation, you want to round down since you don't know where the stone is lodged in the wheel. Therefore, 442 times.

Make sense?

[CaMeL]

1km = 100,000cm
Radius = 36CM
Diameter = 72CM

pi (3.14)(D)=C
(3.14)(72) = 226.08CM

100,000/226.08 = 442.32 times the stone hits the ground

You do not round in this scenerio. the tire will make 1/3 of a final turn but will not hit so the result is 442.32

As a side note, be careful when you teacher asks you to show your work. It may all be correct but if you dont have your stuff in the correct place it will all be considered wrong. For example you have in your pic, 1km = 100,000KM . I knew what you were trying to say but that doesnt mean its not wrong. Just trying to make ya think

[s3lf]

Hai camel:

You would definitely round down in this case. The question doesn't ask for how many tire rotations - it asks for how many times the stone will hit the ground. The stone can't hit the ground 0.whatever times. It can only hit once per revolution, so you need to use a whole number for your answer. Also be sure to use unrounded values carried through your equations even if you present your numbers using significant digits. The final answer should be 442.10 before rounding to 442. Whether you want to use the decimal or the whole number I'll leave up to you.

[eXg. TrueGift]

s**t I messed that up I guess then, after 6:30 I shut my school brain off so yeah... I'll check this out in the morning lmao


scratch that..^


My radius is 36 so I want to find the diameter, the radius is always half the diameter so 36+36= 72 which is my diameter

Then I want to use that so i can find the circumfrence of the tire, so

d= c/pi , 72/3.14= 22.92cm there fore, C=22.92cm, also side note;
1cm=100,000 km

So you want to make 22.92 cm into km right? If so then 22.92*100,000=2,292,000 But! I might be wrong for that last step so can someone figure out where my work is going wrong with the explination I just gave, would help me understand a whole lot better

[eXg.Ground Zero]

s**t I messed that up I guess then, after 6:30 I shut my school brain off so yeah... I'll check this out in the morning lmao


scratch that..^


My radius is 36 so I want to find the diameter, the radius is always half the diameter so 36+36= 72 which is my diameter

Then I want to use that so i can find the circumfrence of the tire, so

d= c/pi , 72/3.14= 22.92cm there fore, C=22.92cm, also side note;
1cm=100,000 km

So you want to make 22.92 cm into km right? If so then 22.92*100,000=2,292,000 But! I might be wrong for that last step so can someone figure out where my work is going wrong with the explination I just gave, would help me understand a whole lot better

What grade you in Con?

[eXg. TrueGift]

I am in grade 9, why

[eXg.Ground Zero]

I am in grade 9, why

He he, thought I reconized the question - oh I was just curious. Reminds me of good ol' grade 9. Dude if you hate grade 9, grade 10 is going to be an epic kick in the ass !!

[SunTzu]

1cm=100,000 km

100,000cm=1km

[eXg. Missy]

s**t i wish it was that easy sstill
wait till physics
i have a 98 in it atm(:

[eXg. TrueGift]

oh s**t eh? LMAO! I wrote it out like that but I still did my answer right and multiplied it by 100,000 because you have to make the number bigger in to km from cm so yea multiply 22.92 by 100,000 or If I am wrong can someone explain it correctly?

[CaMeL]

Radius(2) = your Diameter
Pi x Diameter = Circumference

Next divide 100,000 by your Circumference. and the whole number is your answer. 442

SC2 you are correct my dear sir.

[eXg. TrueGift]

Radius(2) = your Diameter
Pi x Diameter = Circumference

Next divide 100,000 by your Circumference. and the whole number is your answer. 442

SC2 you are correct my dear sir.

Ok i under stand then it'd be 72 x pi = 226.08

72=d btw I'm not figuring this out by calculator and clicking the pi button we are using 3.14 as pi not 3.141592653589793238462643383....

so lets say 72 x pi = 226.08cm, you want to convert cm to km so you multiply ... right?? not divide?

[eXg. Pun1sher]

My head hurts, and I think the tire is FLAT. LOL, now we must take into account the new rolling resitance





kidding

[CaMeL]

Radius(2) = your Diameter
Pi x Diameter = Circumference

Next divide 100,000 by your Circumference. and the whole number is your answer. 442

SC2 you are correct my dear sir.

Ok i under stand then it'd be 72 x pi = 226.08

72=d btw I'm not figuring this out by calculator and clicking the pi button we are using 3.14 as pi not 3.141592653589793238462643383....

so lets say 72 x pi = 226.08cm, you want to convert cm to km so you multiply ... right?? not divide?

well you can do it that way but i live in america so i dont think in km. but you shouldnt have to convert because you already know that 1km = 100,000cm.