Objectives:
Calculates speed.
M6ME-IIIg-17
By: Roy D. Davin
Reviewing previous lesson
Drill: Find the value of x in the ff. equations.
Establishing a purpose for the lesson
Filipinos are found of traveling out of town and out of the country. It is really exciting to go out of the country. Because of technology, we can avail of different promos for cheap airfare as well as accommodation. Have you tried to do so?
2. the pupils will talk about the places they have been to. They will estimate the distance and time they traveled.
Presenting Examples/Instances of new lesson
Present the problem below:
John drove for 3 hours at a rate of 50 miles per hour and for 2 hours at 60 miles per hour. What was his average speed for the whole journey?
Let the pupils analyze the problem. Then find the answer.
Presenting Examples #2
Solution:
Step 1: The formula for distance is
Distance = Rate × Time �Total distance = 50 × 3 + 60 × 2 = 270
Step 2: Total time = 3 + 2 = 5�Step 3: Using the formula�Answer: The average speed is 54 miles per hour.
Be careful! You will get the wrong answer if you add the two speeds and divide the answer by two
Discussing new concepts
Example 1: If a car travels 100kilometers in 2 hours, find the average speed.
Solution:
Using the average speed formula:
Average speed = distance/time
=100/2 = 50 kph
Example 2: a world-record holder ran 800 meters in 86 seconds. What was his average speed rounded to the nearest tenths?
Solution:
Average speed formula:
Ave. speed = distance / time = 800m/86 s =9.3m/s
Watch this video Clip:
Group Activity( Board Work).
1. Grace rides her horse 36 miles in 2 hours 15 minutes. What is the average speed in miles per hour?
2. Pete rides his motorcycle 75 miles in 3 ¾ hours. What is his average speed in miles per hour?
3. An airplane flies 360 km in 1/2 hour. What is its average speed in kilometers per hour?
Practical applications
Group Activity: Distribute an activity sheet to each group.
1.A small robot can travel a distance of 32.5 meters in 13 seconds. What is the average speed of the small robot?
2.5 mph
2.5 mps
0.4 mph
0.4 m/s
2.A truck travels between two cities according to the distance-time graph shown below. What is the truck's average speed for the first hour? What is the truck's average speed for the entire trip?
a.50mph, 5 mph b.40mph, 55 mph c.46.7 mph, 55mph d.55mph, 55
3. A car travels in segments that are described in the table below. What is the average speed of the car?
a.63.67kph b.67 kph c.64 kph d. 63 kph
Making generalizations
How to Calculate Speed?
The Speed can be calculated by finding how much distance traveled by the body and in how much time with respect to the point of observation. Once we find these two things (distance traveled and time taken to travel the distance), we can divide the distance traveled by the time taken to obtain the speed of the object using formula,�Speed = distance/ time
Where �d = distance traveled�t = time taken.
Calculate the speed of the ff. problems:
1. If a car travels 400m in 20 seconds how fast is it going? 2. If you move 50 meters in 10 seconds, what is your speed?
3. You arrive in my class 45 seconds after leaving math which is 90 meters away. How fast did you travel?
4. A plane travels 395,000 meters in 9000 seconds. What was its speed?
5. It takes Serina 0.25 hours to drive to school. Her route is 16 km long. What is Serina’s average speed on her drive to