SpeedSpeed

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What 2 measurements do you need What 2 measurements do you need to know to find the speed of to know to find the speed of something?something?

What is the difference between What is the difference between speed & velocity?speed & velocity?

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What 2 measurements do you need What 2 measurements do you need to know to find the speed of to know to find the speed of something?something?

Distance & timeDistance & time

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What is the difference between What is the difference between speed & velocity?speed & velocity?

Speed is distance / timeSpeed is distance / time

Velocity is speed & directionVelocity is speed & direction

A dog travels 20 meters and it takes A dog travels 20 meters and it takes 2.5 seconds. What is the dog’s 2.5 seconds. What is the dog’s speed?speed?

Speed = Speed = distancedistance time

20 = 8 m/s2.5

““Speed Machines” WorksheetSpeed Machines” Worksheet

Check your answersCheck your answers

Be sure to find the speedBe sure to find the speed

in in miles/hourmiles/hour

600 600 = 150 m/h 4

380 = 760 m/h .5

800800 = 320 m/h = 320 m/h

2.52.5

239239 = 318.67 m/h = 318.67 m/h

.75.75

A. 2200 x 2 = 4400 milesA. 2200 x 2 = 4400 miles

B. 2200 x 3 = 6600 milesB. 2200 x 3 = 6600 miles

C. 2200 x 5 = 11,000 milesC. 2200 x 5 = 11,000 miles

Speed ActivitySpeed Activity

Mrs. Pafundi ran 1 mile in 10.37 min.

1 mile__ 11 min

.09 mile X 60 min 1 min 1 hr

= .09 mi/min

= 5.4 mi/hr

Step 1

Step 2

How many miles/hr?

Step 3 5.4 mi X 1.609 km 1 hr 1 mi

= 8.7 km/hr

AccelerationAcceleration

AccelerationAcceleration

Acceleration – rate at which velocity (speed & direction) changes

Occurs when any of these happen:

•Increase speedexample:

•Decrease speed(also called deceleration)

example:

•Change directionexample:

AccelerationAcceleration

acceleration = final velocity – initial velocitytime time

example:

An airplane starts and travels 40 m/s after 5 seconds. What is its acceleration?

40 m/s - 0 m/s = 40m/s = 8m/s/s = 8 m/s2

5s 5s

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Set up the equation and then solve. Use your notes.

1. As a roller coaster starts down a slope, its velocity is 4m/s. But 3 seconds later, its velocity is 22m/s in the same direction. What is its acceleration?

Initial velocity =

Final velocity =

Time =

4 m/s

22 m/s

3 s

22 m/s - 4 m/s 3 s

= 18 m/s 3 s

= 6 m/s2

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Set up the equation and then solve. Use your notes.

1. A falling raindrop accelerates from 10 m/s to30 m/s in 2 seconds. What is its acceleration?

Initial velocity =

Final velocity =

Time =

10 m/s

30 m/s

2 s

30 m/s - 10 m/s 2 s

= 20 m/s 2 s

= 10 m/s2

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Set up the equation and then solve. Use your notes.

1. A certain car can accelerate from rest to 27 m/sin 9 seconds. What is its acceleration?

Initial velocity =

Final velocity =

Time =

0 m/s

27 m/s

9 s

27 m/s - 0 m/s 9 s

= 27 m/s 9 s

= 3 m/s2