Question

I need help with this problem. I have no idea how to go about solving it.

A 10 inch diameter saw blade spins at 2000 revolutions per minute. What is the angular speed in radians per second? What is the linear speed in feet per second?

Answer 1

how many radians are in 1 revolution?

Answer 2

2pi.

Answer 3

good, then there are 2pi*2000 revolutions per minute

how many seconds in a minute?

Answer 4

60 seconds in a minute.

Answer 5

correct, so lets just do this
\[\frac{2\pi~(2000)~rads}{1~min}\]
\[\frac{2\pi~(2000)~rads}{60~sec}\]

Answer 6

Do I multiply them together, or separately?

Answer 7

i just replaced 1 min byt eh equaivalent 60 secs; then its a simple reduction

Answer 8

my physics teacher would get mad if i didnt do it his way but he got over it when I kept getting the highest grade in the class lol

Answer 9

Okay, so let me make sure I'm doing this correctly - I set my calculator to radian mode, then work out the equation you gave?

Answer 10

radian mode is not needed ... we are not defining any sin cos trig function

Answer 11

I got 200pi/3

Answer 12

since 1 full revolution of a circle is equal to 2 pi radians

then 2000 revolutions will be equal to 2pi * 2000 radians

Answer 13

@amistre64 aha!! now I know who I should tag on my physics problem.

Answer 14

200pi/3 is good; that is the number of radians it is spinning in 1 second

Answer 15

since 1 radian measures an arc of 1 radius; the linear calculation is 200pi/3 * (radius)