What is the speed of the gum as seen by the center of the wheel?

[underoath0101]

4. A train is moving with a speed of 31.4 meters
second . One of the major wheels of the locomotive has a radius of 0.5 meters.
(a) How many revolutions does the wheel make in a second if the center of the wheel advances by 31.4 meters?
(b) A piece of chewing gum, weighing 20.0 grams, is stuck near the rim of the wheel. Determine the force on the gum.
(c) What is the speed of the gum as seen by the center of the wheel?
(d) What is the velocity of the gum (when it is at the top of the wheel) as seen by a person standing on the station?

I was able to solve a, but I keep getting confused on B..b/c i know once you have B you can do F=mv^2/r to get V..idk please help

 

[ehild]

The chewing gum moves together with the wheel, and it is near the rim, so it travels along a circle with radius R. What is the resultant force needed for uniform circular motion?

ehild