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 Answers Put 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

Formulas Speed 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 meters Time = 1 sec. Speed = S ÷ x S

What other formulas can we make from our speed formula?

Distance Formula Distance s = d t d = s x t x t x t

Formulas Time d = s x t t = d s ÷ s ÷ s

Checking for Understanding What is speed? What is the formula for calculating speed?

Example #1 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?

Steps to solving equation 100 m 20 s ÷ x 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. S

Solve in your notebook Ex 2: If you drive at 100 km/hr for 6 hours, how far will you go? 100 km/hr 6 hours ÷ x D 100 km/hr * 6 hours= 600 km

Example #3 ÷ T x 3900 km 100 km/hr 3900 km ÷ 100 km/hr= 39 hours 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? 100 km/hr T ÷ x 3900 km 3900 km ÷ 100 km/hr= 39 hours

Example #4 Ex4: If you run at 12 m/s for 15 minutes, how far will you go?

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?