MOTION AND SPEED Chapter 10

MOTION All matter in the universe is constantly in motion. Examples: 1) Earth revolves around the sun. 2) Electrons move around the nucleus. 3) Blood circulates through your body. 4) Lava flows from a volcano.

MOTION Motion is……. Something that is moving or has movement An object is in motion when it’s changing position relative to a reference point OR it’s distance from another object is changing

FRAME OF REFERENCE A FRAME OF REFERENCE is the stationary point / area / or object that is used as a comparison. What is your frame of reference for the cheerleader and baseball player?

Most Common….. THE SUN AND THE EARTH! What are the most common frames of reference? THE SUN AND THE EARTH!

MEMORY REFRESHER!! What SI units are used to describe length or distance? The basic SI unit of length is the meter.

Distance and Displacement Distance is the total length of travel between a starting point and ending point. Displacement includes the distance between a starting point and ending point AND the direction in which you travel. Distance = 40 m Displacement = 40 m east Distance = 70 m Displacement = 50 m northeast Distance = 140 m Displacement = 0

SPEED! SPEED IS: The distance an object travels in one unit of time.

How do we CALCULATE SPEED? THE SPEED EQUATION: SPEED = Distance ÷ Time DISTANCE TIME SPEED

PRACTICE PROBLEM COMPLETE PRACTICE PROBLEMS A, B, and C on pages 2 and 3 in Packet

TWO TYPES OF SPEED There are two types of speed: Instantaneous Speed and Average Speed Instantaneous Speed: The speed of an object at one instant of time. Can you think of an example? Average Speed: Found when speed is changing by dividing the total distance traveled by the total time taken.

AVERAGE SPEED Complete AVERAGE SPEED SAMPLE PROBLEM on Page 3 of packet!

Look at the Constant Speed graph…. How do you know this dog is running at a “constant” speed? Straight line DISTANCE TIME

Look at the Average Speed Graph What’s happening in the graph? At a? At b? At c? DISTANCE c b a TIME A – moving at a constant speed B – not moving C – moving at a constant speed

VELOCITY What are some examples of direction? Velocity is speed in a given direction! What are some examples of direction? Example: A river is flowing South at 15 km / hr. Velocity = Speed + Direction Velocity = 15 km/hr + South Velocity = 15 km/hr South Complete #13 A & B Velocity Examples

Combining Velocities USE ADDITION AND SUBTRACTION Same Directions ADD the velocities. Opposite Directions SUBTRACT the velocities.

Sample problems page 5 in packet COMBINING VELOCITIES Sample problems page 5 in packet Complete #15; A, B, and C

SO, What is ACCELERATION? Acceleration is the RATE AT WHICH VELOCITY CHANGES!! The process of speeding up or slowing down!

Quick Review Velocity has two components: 1) SPEED 2) DIRECTION

Acceleration 1) Increasing Speed 2) Decreasing Speed Therefore, in science, acceleration refers to three things: 1) Increasing Speed 2) Decreasing Speed 3) Changing Direction

Circular Motion Is the moon accelerating? YES Explain circular motion: Circular Motion – is acceleration because you are constantly changing direction.

Circular Motion Is the ferris wheel accelerating? YES