1-D Kinematics: Graphing Motion

1-D Kinematics Intro: Graphing Motion

Lesson 1

What is Kinematics?

• Study of motion using math.

• Description of motion using mathematics or graphs.

2 kinds of measurements

• Scalar = just magnitude

• Vector = magnitude and direction

Types of Scalar and Vector Measurements

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So what's the difference???

• Distance is the length of the path traveled.

• Displacement is the distance between the start and finish in a straight line.

• Example:

• Distance would be = 6.5 km

• Displacement would be = 2.5 km NORTH-EAST

• huh??? How did you got that!!!!!?!??!!!

Here is how we got the displacement....

Types of Motion

• Distance (length traveled)

• Displacement (distance from start to finish in a straight line)

• Speed (Rate of change of distance over time)

• Velocity (Speed in a given direction)

• Acceleration (Rate of change of velocity over time)

Signs (+ or -) in Motion

• (-) Displacement = moved beyond where you started (0).

• (-) Velocity = moving towards the starting point

• (+) Velocity = moving away from starting point.

• (-) Acceleration = SLOWING DOWN

• (+) Acceleration = SPEEDING UP

Graphing Position

• Sign (+ or -) determines direction moving

• SLOPE = velocity of object

• slope (m) = Rise / Run OR (y2-y1)/(x2-x1)

• Increasing slope = speeding up

• decreasing slope = ???????

What is the Speed of the following object?

• Slope of a position vs time graph = speed

• choose 2 sets of points from graph.

• (x1,y1)(x2,y2)...(8,4)(0,0)

• Plug into m = (y2-y1)/(x2-x1)

• m = (4-0)/(8-0) = 4/8 = 1/2

• Speed = 0.5 km/min

Multiple Choice

Which graph represents forward motion?

• A

• B

• C

• D

Multiple Choice

Which graph represents motion towards the start?

• A

• B

• C

• D

Multiple Choice

Which graph represents an object NOT moving?

• A

• B

• C

• D

Multiple Choice

Which graph represents an object that is slowing down?

• A

• B

• C

• D

Multiple Choice

Which graph is moving the fastest?

• A

• B

THAT'S IT FOR TODAY!

We will look at graphing velocity next class