5.1 Linear and Angular Speed.notebook

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April 05, 2018

Linear and Angular Speeds

What do you know about each of the following?

5 ft 5 ft2 5 ft3 5 ft/sec

Analyzing units tells us what was being measured.

A man walks 10 miles.  It takes 2 hours.  At what speed did he walk?

speed = distance/time

What if the object moving is moving on a circle or on a sphere?

If a runner could run from the North Pole to Beijing, China in 48 hours, then find the speed of the runner.

The central angle formed by the North Pole and Beijing, China is 50o.

The radius of the earth is about 4000 miles.

5.1 Linear and Angular Speed.notebook

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April 05, 2018

For motion on a circle or on a sphere, speed has a new name:

Linear Speed = arc length

time

Find the linear speed of someone standing on the equator of the Earth.

The radius of the Earth is about 4000 miles.

5.1 Linear and Angular Speed.notebook

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April 05, 2018

When an object moves around a circle or on a sphere, the arc length changes with time.

Something else changes also...

If an object on a circle rotates through 360o in 2 seconds, give the angular speed of the object.

Angular Speed =  angle changetime

5.1 Linear and Angular Speed.notebook

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April 05, 2018

A person standing on the equator has what angular speed?

Linear Speed and Angular Speed are connected.

5.1 Linear and Angular Speed.notebook

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April 05, 2018

If an object is moving on a circle and...

...you are given a distance/time, then that is _____________________.

...you are given radians/time, then that is ______________________.

...you are given revolutions/time then that is ___________________________.

The radius of the wheel of a car is 15 inches.

The wheel is turning at the rate of 3 revolutions per second.

Express your answer in miles per hour.

How fast is the car moving?