Answer:
180.07 rev / min
Step-by-step explanation:
Diameter (D) of each wheel =28 inches
Circumference (C) = π x 28 = 28π inches
Conversions:
1 mile = 63,360 inches
1 hour = 60 min
Hence 15 miles / hour
= (15)(63,360) inches / hour
= (15)(63,360) / 60 inches / min
= 15,840 inches per min
Number of revolutions per min = Number of inches per min ÷ circumference in inches
=15,840 inches/min ÷ 28π inches
= 180.07 revolutions per min
