A tractor tire has radius of 30 inches. If the tire is rotating at 80 degrees per second (9/2 seconds to make a full revolution) how fast is the tractor traveling in miles per hour?

Answer 1

c=pid=2pir=2pi(30)=60pi inches per 4.5 seconds

1/17.6 inches per second = mph

60(3.141593)/4.5(17.6) mph

= 2.38 miles per hour

1 inch per second = .0568182 mph

60(3.141593)/4.5 x .0568182 = 2.379995 mph

1 mph = 1760 yds/60 min = 5280 ft/3600 sec = 5280x12/3600 inches per sec

= 528/30 in/s = 176/10 in/s = 17.6 inches per second

1 inch per second = 1/17.6 mph

2 mph = 35.2 in/sec

2.5 mph = 35.2+8.8 = 44 inches per second

3 mph = 52.8 in/sec

60pi/4.5 = 120pi/9 = 40pi/3 = about 41.9 in/sec = between 2 and 2.5 mph

tractors don't go very fast, compared to most vehicles