Speed and Velocity Science_Grade - Seven

speed and velocity

1. Speed and Velocity

2. Objectives: 1. Describe the motion of object in terms of speed and velocity. 2. Design ways to obtain the speed of an object. 3. Differentiate speed and velocity.

3. Speed It is a scalar quantity that refers to "how fast an object is moving." Speed can be thought of as the rate at which an object covers distance. A fast-moving object has a high speed and covers a relatively large distance in a short amount of time. Contrast this to a slow-moving object that has a low speed; it covers a relatively small amount of distance in the same amount of time. An object with no movement at all has a zero speed.

4. Formula s = speed d = distance traveled t = time elapsed Standard Unit m/s Km/ hr miles/ hr

5. Example Problem A car travels a distance of 540km in 6 hours. What speed did it travel at? John is a runner. He runs the 100m sprint in 10s. What speed did he travel at? The distance between two cities is 144km, it takes me 3hours to travel between these cities. What speed did I travel at?

6. 4. A girl cycles for 3hrs at a speed of 40 km/h. What distance did she travel? 5. A train travels at a speed of 16 m/s and travel a distance of 3200 m, calculate the time it takes the train to complete this journey .

7. Activity 3.2 A whale swims at a constant speed of 8 m/s for 17 s. Calculate the distance travelled by the whale. A car travels a distance of 360km in 3 hours. Calculate the speed of the car. John is a runner. He runs the 342m sprint in 9 s. Calculate the John’s speed. A girl cycles for 59s at a speed of 7 m/s. Calculate the distance she travels. A bird can fly at 8 m/s how long would it take the bird to travel a distance of 568m?

8. Seatwork 3. 2 A truck travels down the highway at a speed of 110 km/hr. How long does the trip last if the truck covered 2200 km? A rocket is launched from the launch pad at a speed of 700 km/hr. How far will the rocket have traveled after 1.0 hour? A swimmer can swim 3360 m in 30 seconds. What is her average speed in m/s? A car travels a distance of 603km in 3 hours. What speed did it travel at? John is a runner. He runs the 250m sprint in 50s. What speed did he travel at?

9. Velocity In describing the motion of an object, we do not just describe how fast the object moves. We also consider the direction to where it is going. Speed with direction is referred to as VELOCITY.

10. Formula

11. Example: A man walks to East 7 km in 2 hours and 2 km in 1 hour in the same direction. A car travels North at uniform velocity with a displacement of 100 m in 4 seconds. What is the velocity of the car? Ben walks 10km west to the grocery store. He shops then walks back 10 km east back to his house. What is his velocity? The dog runs heading North 600m and 200 m South in 100s, what was the dog velocity?

12. Seatwork You went biking and drove 8km East in 2 hours and then 3 km West in 1 hour. Solve for your velocity for the entire journey. Dale walks 500m heading North and then 200m back in 100s. What was his velocity? A car travels with a displacement of 16m South in 4s, what is the car velocity?

13. Activity 3.3 COPY AND ANSWER!!! 1. Stan walks 10km west to the grocery store. He shops then walks back 5 km east in 5 hours. What was his velocity? 2. Tyler drives 50km north. Tyler then drives back 30km south in 10 hours. What is his velocity? 3. Brittney travels east 800m and another 200 m in the same direction in 500 s what was her velocity? 4. Anthony walks to the parlor place for hair cut. He walk 4 km east, he realized he passed it and then walked 1 km west in 3hr, what was his velocity? 5. Neil travels 8 m east then 8 m west back in 8s. What was his velocity?

14. Review 1. What is the velocity of a car that traveled total of 75 km north in 1.5 hours? 2. What is the velocity of a plane that traveled 3000 km west from New York to California in 5 hours?

15. Finding the value of displacement and time  

16. Example It took 3 hours for a train to travel the distance between two cities at a velocity of 120 km/h E. What is the car displacement between the two cities? How long would it take for a car to travel a displacement of 200 km W if it is traveling at a velocity of 50 km/h W? A car is traveling at 100 km/h N. How many hours will it take to cover a displacement of 750 km N? A rocket is launched from the launch pad at a velocity of 700 km/ hr E. What will the rocket displacement after 1.0 hour?

17. Activity 3.3 A plane traveled for about 2 hours at a velocity of 1200 km/h north. What is the displacement it traveled? A girl is pedaling her bicycle at a velocity of 135 km/h east. What is her displacement after 3 hours? A girl cycles for 65 s at a velocity of 7 m/s N. Calculate the displacement she travels. A train travels at a velocity of 16 m/s W with a displacement of 928 m, calculate the time it takes the train to complete this journey. A car is traveling at 50 km/h N. How many hours will it take to cover a displacement of 1000 km?

18. Quiz 3.3 Answer x= 6450 km W t= 50 hr = 129 km/ hr W  

19. 2. v= 67 m/s N t= 130s x= vt = 67m/s N x 130 s = 8710 m N

20. 3. v= 100 km/ hr S x= 950km S = = 9.5 hr  

21. 4. x= 22425 m E t= 325 s = = 69 m/s E  

22. 5. v= 30 km/ hr W x= 780 km W = = 26 hr  

23. v= 115 m/s E t = 250 s x= vt = 115 m/s E x 250 s = 28, 750 m E

24. 7. v= 87 km/ hr N t = 4 hr x= vt = 87 km/ hr N x 4 hr = 348 km N

25. 8. v= 12 m/s N x= 960 m N = = 80 s  

26. 9. x= 325 km S t= 25 hr = = 13 km/ hr S  

27. 10.v= 126 m/s E t = 83 s x= vt = 126 m/s E x 83 s = 10, 458 m E