Answer: v = 3.79mph
Step-by-step explanation:
Given:
The diameter d = 122ft
Radius r = 61ft
Time for 2 rev t = 2 mins 18sec = 138s
The rider's speed in rev/sec is given as;
s = 2/138 rev/s
the rider's speed in ft/s is:
v = 2πr × s
v = 2π × 61 × 2/138 ft/s
v = 244π/138 ft/s × 3600s/hr × 1/5280ft/mile
v = 3.79mph
They are traveling at 3.79mph