Just noticed this post and came here off of Google! Unfortunately, the answers are incorrect. I know this because I just did a similar problem such as this one and I figured I'd go on here and complete the problem. Here's the answer to your question (I know I'm years late, but here it is anyways!)
a. Find the angular speed of the wheel.
So to get the angular speed of the wheel, you need to take the number of revolutions per minute and multiply it by the angle (in radians) it turns per minute. This will give us the radians per minute, which is the 'angular speed' that we are looking for. In this equation, π = pi (3.14159...)
angular speed = (200 revolutions / 1 minute) * ([2 * π] radians / 1 revolution)
angular speed = 400π radians per minute.
Note that doing this will cancel out the 'revolution' units and you will be left with minutes and radians - which is the units we need for angular speed.
b. Find the linear speed in cm/sec of a point on the cd that is 5.7 cm from the center.
Here to get the linear speed of the wheel, you need to use this formula (where s/t is linear speed, θ/t is angular speed, and r is the radius.) The equation looks like this:
s / t = r * (θ/t)
From here you just find the angular speed plugging in the values given to you in the problem. r = 5.7 cm; (θ/t) = 400 radians/min; (s / t) = what we need to find.
Hence...
s / t = 5.7 cm * (400π radians / 1 minute) = 2280π centimeters per minute
However, we aren't finished yet. Notice the problem asks for the units in centimeters per second! So here we need to do unit conversions to cancel out minutes and replace them with seconds. We do it like this:
linear speed = (2280π centimeters / 1 minute) * (1 minute / 60 seconds) = 38π centimeters per second
Making 38π cm/sec your linear speed!
I know nobody asked me to do this problem, but I hope I helped! I checked with my professor and some other students, and it looks like this is the right answer. Happy solving!