MOTION

How speedy are you?

Speed Trivia

Question #1

• What is the world’s fastest animal?

Peregrine Falcon• Top speed when in a hunting dive • 200 mph or 322 km/hr

But…Fastest land animal: cheetah

(70 mph, 113 km/h)

Fastest sea animal: sailfish (up to 68 mph, 110 km/h)

Question #2

• What is the fastest speed a human can run?

Usain Bolt• World Record holder

• 100m = 9.58 sec (38 km/h, 23 mph)http://www.youtube.com/watch?v=3nbjhpcZ9_g

Question #3

• What is the fastest car?

• Bugatti Veyron: 267 mph (441 km/h)• 0-60 in 2.5 secs • $1,700,000 (US)

Question #4

• How fast does a rain drop fall?

It depends…

• On size and weight of rain drop• On wind resistance• Average = 7 mph, 3 m/s

Question #5

•What is the fastest train?

Shanghai Airport Maglev• 430km/h = ~269 mph

Question #6

• How fast is the speed of light?

299,792 kilometers per second = 1,079,251,200 km/hr !!!186,287 miles per second = 670, 633,200 mph

• A traveler, moving at the speed of light, would circumnavigate the equator approximately 7.5 times in one second. By comparison, a traveler in a jet aircraft, moving at a ground speed of 500 mph, would cross JUST the continental U.S. once in 4 hours.

• It takes 499.0 seconds (8 min) for light to travel from the Sun to the Earth

Question #7

• How fast does hair grow?

• Average 1.25 centimeters or 0.5 inches per month

• 15 centimeters or 6 inches per year

• Depends on age and health

http://alt.coxnewsweb.com/ajc/swf/blueangels/blueangels.swf

SPEEDBack seat of an F-18

Question #8

• Is motion relative? • Yes or No?

Are we ever really standing still?

Yes, All things are in motion.

• You may be perfectly still yet the earth is spinning on its axis and orbiting the sun.

• The sun orbits the center of the galaxy, our galaxy and Andromeda are moving toward one another, most of the other galaxies are moving away.

So to measure motion in a meaningful way, we measure it relative to the observer or another object we consider not to be moving.

When you pass a car on the highway moving in the same direction, you may be going 70mph, and the other car 65mph. But your speed relative to the other car is 5mph.

When the shuttle docks with the space station the two orbiting objects approach one another at a very slow speed relative to one another, but both are orbiting at 17,000mph relative to the surface of the earth.

•Motion is a change in position relative to your surroundings.

•An object moves when it speeds up, slows down or changes direction.

Main IDEAS

What’s a Frame of Reference?

BACKGROUND OR OBJECT

USED FOR COMPARISON

SPEED rate at w/c an object moves

Distance (D)

Speed =

Time (T)

d

ts

Another way to express this is in a “formula triangle” like this:

SPEED IS….

Inversely Inversely Proportional toProportional to TIMETIME

Greater speed, less time

Less speed, more time

DIRECTLY PROPORTIONAL TO

DISTANCE

An ant crawled 12 inches in 10 seconds. A second ant crawled 24 inches in 10 seconds.

Compare the speed of the ants.

A plane flew 220 meters in 1 second.

A second plane flew 220 meters in 2 seconds.

Compare their speeds.

DISTANCELength between two places

Distance = speed x time

D= ST

Expressed in km (1000m)

TIME

=

d s

T

CONSTANT SPEED

SPEED THAT DOES NOT CHANGE

CONSTANT SPEED

STEPS IN PROBLEM SOLVING

STEP 1. Write the formula

STEP 2. Substitute given numbers and units STEP 3. Solve for the

unknown.

SAMPLE PROBLEM:

At what speed did a plane fly if it traveled 1760 meters in 8 seconds?

SOLUTIONStep 1. Speed = Distance/Time

Step 2. Speed = 1760 meters/ 8sec

Step 3. Speed = 220 m/sec

SAMPLE PROBLEMS:1. A car travels 240 kilometers in

3 hours. What is the speed of the car during that time?

ANSWER: S= d/t S= 240 km/3 hr

80 Km/Hr

The speed of a cruise ship is 50 km/hr. How far will the ship travel in 14 hours?

Answer: D = ST 700 km

AVERAGE SPEED

TOTAL DISTANCE / TOTAL TIME

AVERAGE total distance traveled

SPEED time=

AVERAGE SPEED

A car travels 200 m in 10 seconds. What is the average speed of the car?

ANSWER: Ave speed= total d/total time

= 200m/10s

20 m/s

Definitions:

A change in position in a certain amount of time is __________.

__________________ is the rate at which an object moves and is determined by dividing ____________ by _____________.

_________________________ is speed that does not change.

_________________________ is calculated by dividing the total distance by the total time.