Motion!. Key Ideas An object in motion changes position. Speed measures how fast position changes. Acceleration measures how fast velocity changes.

Presentation on theme: "Motion!. Key Ideas An object in motion changes position. Speed measures how fast position changes. Acceleration measures how fast velocity changes."— Presentation transcript:

1 Motion!

2 Key Ideas An object in motion changes position. Speed measures how fast position changes. Acceleration measures how fast velocity changes.

3 Position Position = location of a place or object Reference Point = location to which you compare other locations You need a reference point to describe a location. Examples: Tyler is sitting next to Sarah. Santiago, Chile is about 3000km southwest of Brasilia, Brazil.

4 Latitude and Longitude

5 Distance May be straight-line length or length of a path or route Standard unit of measure is meters (m) Longer distances use kilometers (km) Shorter distances use centimeters (cm)

6 From Hickory to Holly Ridge Straight-line distance: 373 km (232 mi) Travel distance: (307 mi)

7 Motion Motion = a change in position over time A change in position is evidence that motion has happened

8 Relative Motion How you see an object’s motion depends on your own motion. http://www.youtube.com/watch?v=7gu 1XDGSbe8 http://www.youtube.com/watch?v=7gu 1XDGSbe8 Which direction is the corvette moving in relation to the mustang? Which direction is the mustang moving in relation to the corvette?

9 Speed Speed = measure of how fast something moves, or the distance it moves in a given amount of time Greater the speed, faster object changes position Speed = distance/time, S = d/t Meters per second – m/s Kilometers per hour – km/h

10 Average Speed Speed is not constant Calculate speed over a specific distance Example = time each lap and add those times together, then average

11 Distance-Time Graphs Shows how distance and speed change over time Plots distance an object travels against the time

12 Velocity Velocity = speed in a certain direction Changes in direction or speed change velocity Examples: Does a car traveling west at 100 km/hr have the same velocity as a car traveling east at 100 km/hr? Does a car traveling east at 100 km/hr have the same velocity as a car traveling east at 75 km/hr?

13 Vector Vector = a quantity that has both size and direction Velocity is a vector because it has a size (speed) and a direction

14 Velocity vs. Speed Walking north from home to the store you travel at a speed of 5 km/h. Walking south back home from the store you travel at the same speed of 5 km/hr. Speed is still 5 km/hr But velocity is 0 km/hr because you ended up where you started!

15 Acceleration Acceleration = rate at which velocity changes

16 Types of Acceleration In same direction as motion Speeding up In opposite direction of motion Negative acceleration, slowing down At a right angle to motion Change direction but speed is the same

17 Formula for Acceleration

18 Velocity-Time Graph