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....

Fill in the Blanks

What is the distance travelled in this problem? (include units in answer)

Fill in the Blanks

What is the displacement in this problem? (include units in answer)

Fill in the Blanks

What is the distance travelled in this problem? (include units in answer)

A child walks 5 m east, then 3 m north, then 1 m east.

Fill in the Blanks

What is the displacement in this problem? (include units in answer)

A child walks 5 m east, then 3 m north, then 1 m east.

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

Fill in the Blanks

Calculate the speed of the object when it is moving away from the start. (include units)

THAT'S IT FOR TODAY!

We will look at graphing velocity next class