Friday, Nov 7, 2014

1.Turn in Homework!

2.Take Quiz

3.Average Speed Notes in your Journal!

4.Average Speed Practice Problems

Lesson Objective:

Students will be able to calculate average speed using distance and time measurements.

Demonstration of Learning:Students will complete 10 average speed practice problems with 100% accuracy.

Speed •Speed is how fast an object moves in a certain amount of time.

•Speed hardly ever stays constant. Objects speed up, slow down, stop, and start again.

Instantaneous Speed vs.

Average Speed

Instantaneous Speed•Something’s speed at one moment.

Average Speed •How fast something goes during a

whole trip, on average.

• AVERAGE SPEED is the average of all the speeds an object has traveled in one trip or trial.–Example: When you walk from

Mrs. Smith’s room to Mr. Stroud’s room, you will speed up & slow down along the way. Your AVERAGE SPEED is a summary of all the speeds you went along the way.

• What information do you think you would need to calculate how fast you, someone else, or an object traveled?

Average Speed•When finding the average speed of an object, we use a simple formula

S (s = speed, d = distance, t = time)

• We find average speed by dividing the total distance traveled by the total time it took to travel.Average speed = total distance ÷ total time

Example: Distance = 1,761 steps Time = 3 minutes

Divide: 1,761 ÷ 3 = ____ steps/min.

We read this “steps per minute.”

What exactly is “distance”?

Distance•Distance is the amount of space between two things or people.

What are examples of units

for distance?

Distance Units •Centimeters• Inches•Feet•Meters•Yards•Kilometers•Miles

What exactly is “time”?

Time•Time is how long something takes.

What are some examples of units

for time?

Time Units • Seconds•Minutes•Hours•Days•Weeks•Months• Years•Decades• Centuries

Units• This gives us our units for average speed!

• We use the units for distance and time that are given to us in the problem.

DistanceCentimeters, Inches, Feet, Meters, Yards, Kilometers, Miles, etc. Speedkm/hrm/scm/scm/hr

TimeSeconds, minutes, hours, days, weeks, months, years, etc.

Example 1 If a car drives 30 kilometers in one hour, what is its average speed?

Example 2 A motorcycle traveled 250 kilometers in 5 hours. What was the average speed?