Velocity - Kinematics | Show Me The Physics

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Velocity - speed in a particular direction

Fill In The Blanks Notes

Watch the Animation Below

Velocity is speed in a particular direction. How many velocities does a curveball have? (ignore spin)

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3 Motions

Forward, Left (or Right), Down

Velocity - Speed in a Particular Direction

How many velocities does this boat have?

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Video Instruction

showmethephysics.com

Enduring Understanding

1. Velocity is the speed in a particular direction.

2. Velocity is the change in displacement per unit time. + is up, right, east and forward.

3. An object can have one speed but 3 velocities. (Curve Ball)

C. Velocity

Speed in a particular direction

Football player running to catch the ball

Velocity & Direction [ HTML5 ]

showmethephysics.com

Focus on the man walking across this page. Identify his 2 velocities. Which is the greater of the two?

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The answer depends on your coordinate system. The man is moving to the north (or up, forward, y) and the east (or across, to the right, x). Since his easterly displacement is greater, he has a greater easterly velocity.

Ex) Joe Drove 13 Meters Northeast in 2.0 Seconds

What was Joe's...

Northeast displacement? displacement east? displacement north?

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Northeast displacement? 13 m NE displacement east? 12 m E displacement north? 5.0 m N

We can say that Joe has 3 velocities:

V = 6.5 m/s N.E.

V = 5 m North / 2 seconds
= 2.5 m/s North

V = 12 m East / 2 seconds
= 6 m/s East

1. Velocity Is Always Written With Direction

Examples: 5.0 m/s east • +5.0 m/s • 100 m/s downward • −100 m/s

2. Equation

V = Δd/Δt

For straight line motion: V = distance/time and direction

Honors Extension

FrameRef_WallMoves.mov

Check Your Understanding

5 quick questions — pick an answer to see if you’re right.

1. What is velocity?

2. Ignoring spin, how many velocities does a curveball have as it travels toward the plate?

3. A car drives 10 m northeast in 2.0 s, which is 8 m east and 6 m north. What is its northward velocity?

4. A runner travels 100. m east in 20. s. What is the runner's velocity?

5. Which of these is correctly written as a velocity?

Acceleration →