angular and linear speed & find angel of elevation  TOPIC_SOLVED

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angular and linear speed & find angel of elevation

Postby maria1983 on Sat Mar 07, 2009 10:03 pm

1. A wheel has a radius of 14 feet. The wheel is rotating at 21 revolutions per minute. Find the angular and linear speed. Leave your answer in terms of "pi".

what is angular and linear speed?

2. A guy wire fifty feet long is attached to the top of a pole forty feet tall. THe wire is also attached to the ground at a point thirty feet from the base of the pole. Find the angle of elevation. Round your answer to two decimal places.

i did a picutre but what next?
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Postby stapel_eliz on Sat Mar 07, 2009 11:52 pm

maria1983 wrote:1. A wheel has a radius of 14 feet. The wheel is rotating at 21 revolutions per minute. Find the angular and linear speed. Leave your answer in terms of "pi".

what is angular and linear speed?

"Angular speed" should be defined in your book. There is more than one definition. But since "21 revolutions per minute" is given in the exercise, that's probably not what they want. Maybe "radians per minute", with one rotation being radians...?

"Linear speed" is the distance you'd cover on the ground if the wheel were rolling down the road. You find the circumference (using ) and then multiply by the number of times that circumference has spun around.

maria1983 wrote:2. A guy wire fifty feet long is attached to the top of a pole forty feet tall. THe wire is also attached to the ground at a point thirty feet from the base of the pole. Find the angle of elevation. Round your answer to two decimal places.

i did a picutre but what next?

Use one of the trig ratios for a right triangle. Once you've set up the ratio, use the "inverse (whatever trig function you've chosen)" button on your calculator to find the angle measure.

Make sure the calculator is in "degree" mode! :wink:
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Re: angular and linear speed & find angel of elevation

Postby maria1983 on Wed Mar 11, 2009 12:39 pm

stapel_eliz wrote:
maria1983 wrote:2. A guy wire fifty feet long is attached to the top of a pole forty feet tall. THe wire is also attached to the ground at a point thirty feet from the base of the pole. Find the angle of elevation. Round your answer to two decimal places. i did a picutre but what next?
Use one of the trig ratios for a right triangle. Once you've set up the ratio, use the "inverse (whatever trig function you've chosen)" button on your calculator to find the angle measure. Make sure the calculator is in "degree" mode!

i did sin(angle)=40/50 then i did sin-1 on 40/50 i got 53.13010235 is this rite?
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Postby stapel_eliz on Wed Mar 11, 2009 3:12 pm

maria1983 wrote:i did sin(angle)=40/50 then i did sin-1 on 40/50 i got 53.13010235 is this rite?

Remember to label (with the "degree" symbol), and to round to the specified number of decimal places. :D
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