a) Linear velocity, v = ωr ω = Angular velocity, r = radius.
ω = 5 revolutions per minute. 1 minute = (1/60) hour. 
= 5*2π radians / (1/60) hour = 600π radians per hour π = 3.14 
= 600*3.14 = 1884 radians / hour
but radius, r = 10 feet, 5280 feet = 1 mile, 10 feet = (10/5280) mile 
Linear velocity, v = ωr
 v = 1884 radians / hour * (10/5280) mile 
 v ≈ 3.568 miles / hour