Motion

1. Motion • An object changes position, over time, compared to (a) reference point(s). • If this sounds picky… • it can be hard to tell if you’re moving. On an airliner, you’re going 500+ mph but it feels like you’re standing still. • Until turbulence changes the plane’s velocity

2. Motion is Relative! • A girl standing still tosses a ball in the air, it looks like the ball goes up and down. • If you’re both in a car going 55 mph, to you it looks like the ball is going up and down while the world is rushing by. • To a kid waiting at a crosswalk in Linton the ball is going forward as fast as the car and up and down as well.

3. Are the stars moving or are we? • Ancient people thought the stars were moving and the Earth stood still. • Thanks to Copernicus and Galileo we now know that the Earth is moving and so are the stars. • We are standing on a planet spinning on it’s axis, orbiting the sun that is a part of a spinning galaxy expanding outward every moment...but it feels like we’re standing still.

4. How do We Measure Motion? • Speed = rate of change in position • Speed = distance ÷ time • s = d/t • When you’re in a car speed is measured in miles (distance) per hour (time) or mph.

5. Example: A car went 110 miles in 2 hours, what is its speed in mph? • First write out the formula s=d÷t • Plug in the numbers (include units) s= 110miles ÷ 2 hours • Do the math; s= 55 mph • Your answer must include units.

6. Example 2: Rare Bear 528.33 mph • Fastest piston engine propeller plane ever. • Portland to Clatskanie (~78.0 miles) in 8.9 minutes! What’s it’s speed in miles per minute? • S= d ÷ t • S = 78.0 miles ÷ 8.9 minutes • S = 8.8 miles per minute (Clatskanie to Rainier in 82 seconds!)

7. Speed Machines • You will need this handout.

8. 1. One of the fastest Nascar racers on the circuit recently traveled 600 miles in 4 hours? What is the car’s average speed? • Speed = distance ÷ time • Speed = 600 miles ÷ 4 hours • Speed = 150 mph

9. 2. The German-made Thrust SSC is the fastest car on Earth. It covered a one mile course in 0.0013 hours. What was its speed in miles per hour? • Speed = distance ÷ time • Speed = 1mile ÷ 0.0013 hours • Speed = 769 miles/h Click on the image to play

10. 3. The fastest train on Earth, the TGV from France, traveled 800 miles in 2.5 hours. What was its average speed? • Speed = distance ÷ time • Speed = 800 miles ÷ 2.5 hours • Speed = 320 mph Video

11. 4. The Spirit of Australia a hydroplane, broke boating speed records by traveling 239 miles in 0.75 hours (45 minutes). What was its record breaking speed? • Speed = distance ÷ time • Speed = 239 miles ÷ 0.75 hours • Speed = 319 mph

12. 5. The fastest plane ever, the SR-71 Blackbird, in a record breaking flight went from Los Angeles to Washington D.C. (a distance of ~2,300 miles) in about 1.06 hours. What was its speed on this record setting trip? • Speed = distance ÷ time • Speed = 2,300miles ÷ 1.06 hours • Speed = 2,167 mph video

13. 6. The X-15 was faster, but did not take off under it’s own power, it was dropped from a B-52 mother plane. After clearing the mother and igniting it’s engines, the X-15 could travel 960 miles in 0.2 hours. What was it’s speed in miles per hour (mph)? • Speed = distance ÷ time • Speed = 960 miles ÷ 0.2 hours • Speed = 4,800 mph Movie

14. 7. The fastest air breathing unmanned craft, the X43A scramjet, it reached Mach 6.8 (Mach 1 = speed of sound). At this speed it could travel 7752 miles in 1.5 hours. What is it’s speed in miles per hour? • Speed = distance ÷ time • Speed = 7752 miles ÷ 1.5 hours • Speed = 5,168 mph video

15. Fastest Humans Ever! ? Apollo launch The highest speed ever achieved by a manned vehicle is 39,895 km/hr (24,790 mi/hr). What was the vehicle and who were the three voyagers inside? Answer: Apollo 10 (1969) during reentry.

16. Velocity is Not the Same as Speed. • Velocity is speed plus direction. • Velocity can change if an object speeds up, slows down, or changes direction

17. Acceleration = Vfinal – Vinitial Time or = ∆Velocity Time

18. Acceleration Causes a Force You Can Feel. • When a car speeds up rapidly, you are pushed backward. • If the car stops abruptly, you lurch forward. • If the car goes fast around a sharp corner, you are pushed toward the outside of the corner.

19. Example: A car goes from 10 mph to 50 mph in 4 seconds, what is its acceleration • Write down the formula; a= change in speed ÷ time • Plug in the numbers; a = (50 mph – 10 mph)÷ 4 sec • Do the math a = 40mph ÷ 4 sec = 10mph/sec

20. You will need this handout

21. 1. What is acceleration? How can you tell if you are accelerating? You feel a force You’re speed might be the same, but you’re velocity is changing You’re speeding up, slowing down, or changing direction.

22. 2. A Lamboghini Murcielago LP640 went from 0 to 60mph in 3.3 seconds what is it’s acceleration in m/h/s? • a = Vfinal – Vinitial÷ time • a = (60mph – 0mph) ÷ 3.3 sec. • a = 18.8 miles/h/s

23. 3. The Ford RS200 Evolution did 0 to 45mph in 2.1 seconds what is it’s acceleration in miles/h/s? • a = Vfinal – Vinitial÷ time • A = (45 mph – 0mph) ÷ 2.1 sec. • a = 21.4 miles/h/s

24. 4. The Bugatti Veyron did 30 to 60 mph in 1.25 seconds. What is it’s acceleration in miles/h/s? • a = Vfinal – Vinitial÷ time • a = (60mph – 30mph) ÷ 1.25 sec. • a = 24 miles/h/s

25. 5. Mr. Kay’s SUV goes from 60mph to 0mph in 6.2 seconds. What is it’s acceleration? (be careful, is he going faster or slower?) • a = Vfinal – Vinitial÷ time • a = (0mph – 60mph) ÷ 6.2 sec. • a = -9.8 miles/h/s • He is slowing down to a stop.

26. What is each car doing? • The blue car (squares) • is standing still • The red car (diamonds) • is going at a slow constant speed • The green car (triangles) • is accelerating D i s t a n c e Time