O B J E C T I V E : T O D E F I N E A N D C A L C U L AT E S P E E D .

DO NOW: WHAT IS THE SPEED OF AN OBJECT THAT IS

STANDING STILL?

TIME….• It can mean either a moment in time like when you ask, “What time is it?” OR….• It can mean a quantity of time, for example how long did something take to occur? We use the second (sec) as our basic unit of time.

SPEED & CONSTANT SPEED

• What is the difference? What do we mean by the word constant?

• Speed describes movement from one place to another over time; we say it’s the distance divided by time.

• Constant speed is a maintained speed that does not change. This means the same distance is traveled every second.

NOW IT’S YOUR TURN…

•With your table partner, come up with 3 variations for the formula for speed AND•Three different units you could use.

Why do we use v?V stands for velocity, which indicates that you know direction as well as speed.

WHAT ARE THE UNITS?

•Meters per second•Kilometers per hour•Centimeters per second•Miles per hour• Inches per second•Feet per minute

NOW LET’S PRACTICE CALCULATING… WORK WITH YOUR PARTNER TO SOLVE

1. What is the average speed of a car that traveled 300.0 miles in 5.5 hours?

2. A bicyclist, traveling at 22 miles per hour, rides a total of 44 miles. How much time, in hours, did it take?

3. How far can a person run in 15 minutes if he or she runs at an average speed of 16km/hr? Hint make sure your time is in the same units!

4. You ride your bike for a distance of 30 km. You travel at a speed of 0.75 km/minute. How many minutes does this take?

• Answers: 1. speed = distance / time….

300 miles/5.5 hours = 2. Time = distance /speed

44 miles/22 miles/hour

3. Distance = speed * time 15 minutes * 1 hour/60 minutes = 0.25 hours

16 km/hour * 0.25 hours =

4. Time = distance /speed30 km / 0.75 km/minute

WHAT DID WE LEARN???

• What do we mean by the term constant speed?

• What are the variables when calculating speed?