Answer: 315.3 min^-1
Explanation:
Given the following :
Speed = 45miles per hour
Diameter of wheels = 48inches
Number of complete revolutions the wheel makes in one minute =?
Since wheel diameter is in inches, we convert speed (miles/hour) to inch per minute
1 mile = 63360 ; 60minutes = 1 hour
45 miles / hour = (45 × 63360) / 60
= 2851200 inch/60 min
= 47520inch/min
Distance covered per revolution:
Circumference of a circle (C) = 2πr
Where r = radius ; r = diameter / 2
r = 48/2 = 24 inches
C = 2 * 3.14 * 24 = 150.72inches
Number of revolutions per minute:
Speed per minute / distance covered per revolution
(47520inch/min)/ (150.72 inch)
= 315.286 min^-1