Do Now 1. Put these objects in order from slowest to fastest:• Peregrine falcon• Cheetah• Ms. Lusk• Car (at the highway speed limit)• Mako shark• Ocean wave• Maglev train

Do Now AnswersPut these objects in order from slowest to fastest:• Peregrine falcon (#6, 200 mph)• Cheetah (#5, 70 mph)• Ms. Lusk (#7, 351 mph: JK #2, 28 mph)• Car (at the highway speed limit) (#4, 60 mph)• Mako shark (#3, 31 mph)• Ocean wave (#1, 4.5 mph)• Maglev train (#7, 350 mph)

Announcements

• Quiz over motion, speed, and velocity on Monday.

• Lab tomorrow • Parent Lab Night: A week from today

– If you need another invitation, please see Ms.Lusk

– PLEASE come. It’ll be fun

Speed, Distance, and Time

What is speed?• Speed is a measure of how fast something

moves or the distance it moves, in a given amount of time.

How do we calculate speed?

• To calculate speed, we have to use a formula.

• Speed=Distance divided by Time

FormulasSpeed

speed = distance

time

s = d

t*speed of a car is mph = miles = distance

hour time

Speed Triangle• To help us solve speed problems, we can

use a speed triangle like the one below.

D

S T

÷

x

How do we use this?

• Step 1: Draw a triangle on your paper.• Step 2: Write in the numbers that you know

from the problem. – MAKE SURE THEY ARE IN THE CORRECT

PLACE!• Step 3: Use your finger to cover the section of

the triangle that you are solving.– If one number is on top of the other, divide.– If two numbers are next to each other,

multiply.

4. Distance = 10 metersTime = 1 sec.Speed = S

S

10 m

1 s

÷

x

What other formulas can we make from our

speed formula?

Distance FormulaDistance

s = d

t

d = s x t

x tx t

FormulasTime

d = s x t

t = d

s

÷ s÷ s

Checking for Understanding

• What is speed?• What is the formula for calculating speed?

Ex1: A football field is about 100 m long. If it takes a person 20 seconds to run its length, how fast were they running?

Example #1

Steps to solving equation

Step one: Identify your distance and your time.

D= 100 m T= 20 sec

Step two: Place numbers into the triangle. Step three: Solve for distance.

100 m

20 s

÷

x

S

Ex 2: If you drive at 100 km/hr for 6 hours, how far will you go?

Solve in your notebook

100 km/hr 6 hours

÷

x

D100 km/hr * 6 hours= 600 km

Every summer I drive to Michigan. It is 3900 km to get there. If I average 100 km/hr, how much time will I spend driving?

Example #3

100 km/hr T

÷

x

3900 km3900 km ÷ 100 km/hr= 39 hours

Ex4: If you run at 12 m/s for 15 minutes, how far will you go?

Example #4

Average Speed• Speed is not constant.•Ms.Lusk and a half marathon •To calculate average speed find the distance

traveled, and then divide by the sum of the times.

Example #5

An excellent middle school runner might have the following times for the four laps of the 1600-meter race: 83 seconds, 81 seconds, 79 seconds, and 77 seconds.

• Step One: Identify the distance traveled.• D=16oo m

• Step Two: Add up the seconds it took to complete.• T= 320 sec

• Step Three: Place into equation• S = 1600 m• 320 sec

• Step four: Solve equation • 5.0 m/sec

On your own A ball is thrown a total of 18 meters in 3 seconds. What is the average speed of the ball?