Question

Can someone please help me out with this question!!! I have no idea where to start. The question is stated below:

A typical industrial windmill has rotating blades that are each 116 ft long. From a distance, you observe that it takes a single blade 3.5 seconds to make a full rotation. How fast is the outer tip of the blade moving? Give your final answer in miles per hour.

Answer 1

The tip makes a circle as it rotates. What is the circumference of this circle?

Answer 2

728.48

Answer 3

yes roughly, so it travels approximately 728.48 ft in 3.5 seconds

Answer 4

3.5 seconds = 3.5/3600 = 0.000972 hours

728.48 ft = 728.48*(1/5280) = 0.1379697 miles


"the tip travels approximately 728.48 ft in 3.5 seconds"

is equivalent to saying

"the tip travels approximately 0.1379697 miles in 0.000972 hours"

Answer 5

Divide the two (distance/time) to get the speed in mph

make sure you use the miles and hours

Answer 6

why do you divide 3.5/3600

Answer 7

because

1 hr = 60 min
1 min = 60 seconds

so 1 hr = 60*60 = 3600 seconds

Answer 8

3.5 seconds turns into 0.000972 hours (roughly) when you use the conversion 1 hr = 3600 seconds

Answer 9

so would my answer be 141.9441358 miles per hour

Answer 10

correct

Answer 11

thank you!

Answer 12

yw