How Do You Calculate the Angular and Linear Speed of a Ball?

[imy786]

Homework Statement

a ball moves at 5000 rpm (revolutions per minute). Their radius is 4 cm.

(i)Determine the angular speed in radians per second.

(ii) Find the period of rotation

(iii) Find the linear speed of a point on the outer ball

(iv) Find the linear acceleration of a point on the outer edge of the ball.

Homework Equations

angular speed = 2∏ / T

The Attempt at a Solution

(i)

r = 4cm = 0.04m
circumference = 2∏r = 0.08∏

1 rev = 2∏°
5000 rev/min = 5000 X 2∏° / min
10,000∏° / min
10,000∏° / min = 10,000∏° per 60 secs

10,000∏° / 60 = 166.67∏°/sec

angular speed = 166.67∏°/sec

is this correct for part (i)

 

[Spinnor]

I think so, see,

http://www.convertunits.com/from/radian/second/to/RPM

Found via,

http://www.google.com/webhp?hl=en#h...w.,cf.osb&fp=287cb8a321ceab01&biw=721&bih=408

 

[lightgrav]

1 rev = 2∏ radians = 360° ; be careful with your units.
You might as well say that omega = 523.6 rad/sec.

 

[imy786]

Find the period of rotation

T = 2 ∏ / omega = 2∏/523.6 = 0.012 seconds

 

[imy786]

is this correct?

 

[imy786]

why isn't anyone responding?