Question

the circular blade on a saw has a diameter of 7.5 inches and rotates at 2400 revolutions per minute.
A) find the angular speed in radians per sec
B) Find the linear speed of the saw teeth ( in feet per sec) as the contact the wood being cut.

Formulas--> Linear speed= arc length/time= s/t
Angular speed= central angle/time
arc length s= radius r * central angle(in radians)

Answer 1

the answer in the book is 80pi rad per sec for a and 25pi ft per sec for b but i dont know how to get to that...

Answer 2

There are 2pi for every revolution

Answer 3

so we multipy 2pi * 2400
this is angular speed in minutes, we want is in sec ; so divide by 60
2pi * 2400/60 =80pi

Answer 4

linear speed = radius time angular speed

Answer 5

radius= 7.5/2=3.75 inches=.3125 feet

Answer 6

b)linear speed = radius x angular speed
.3125 x 80pi=25 pi

Answer 7

ur wrong you wouldn't divide by 60 you would multiply thus getting the wrong answer

Answer 8

for the min to sec thing

Answer 9

but it matches your answer

Answer 10

the angular speed is wrong you would multiply 60 to convert min to sec

Answer 11

If I run 60 miles per minutes, how many miles do I run in a second?

Answer 12

1 mi per sec?

Answer 13

yeah, did you divide or multiply by 60?

Answer 14

divide

Answer 15

2400 1 min
-----*------ = 240/6 rps
1 min 60 sec

Answer 16

okay i got what your saying thanks :) and im sorry that i said you were wrong

Answer 17

no problem, glad to help