Question

a wheel, including the tyre, has a radius of 26cm. how many complete revolutions will the wheel make in travelling 1km? I have no clue how to do this any help please :)

Answer 1

here the key is to find the circumference , can you do that using the given information

Answer 2

to work out the circumference you got to do the radius times pi but i don't know how to do it with this :/

Answer 3

the circumference of a circle is givne by : 2*pi*r

Answer 4

in our case you would have to solve: 2*3.14*26

Answer 5

whats 2*pi*r? and i am now lost lol

Answer 6

that is the formula for the circumference of a circle, or in this case the wheel (since a wheel is shaped like a circle)

Answer 7

yeah i get that bit

Answer 8

basically we are gonna use this formula because we need to find out how much distance the wheel travels in one revolution. By finding the circufernece we area basically cutting the wheel down the middle and flattening out the wheel so that we can see just how much distance the wheel covers

Answer 9

ok i've done that now, so do i have to do 26*pi=..../2 ?

Answer 10

the formula is: 26*2*3.14. That should give you: 163.28

Answer 11

ok thank you

Answer 12

now there should be a unit attached to that, in this case it would have to be 163.28 cm

Answer 13

so the wheel covers 163.28 cm in one revolution

Answer 14

it sounds so simple now thank you very much :)

Answer 15

now all we need to find is how many cm are in 1km

Answer 16

100cm = 1 meter.

1 km = 1000 meters

1 km = 1000 * (1 meter) = 1000 * 100 cm = 100000 cm.

Answer 17

Thus we see that 1km is actually equal to 100000cm

Answer 18

yeah do i have to dive 100000 by 163.28

Answer 19

yup, that is the last step

Answer 20

thank you

Answer 21

you just got schooled

Answer 22

lol

Answer 23

so is the answer 612.14 cm ?

Answer 24

The answer should be 612.4 revolutions. If your teacher wants a whole number you can round it to 612 revolutions

Answer 25

yeah thats what i got .

Answer 26

:)