1. Motion

2. What Do We Mean By Speed? Exactly how fast are you running? How many meters do you run for each second? Do you always run the same number of meters each second?

3. Speed The speed of an object is a measure of how quickly the object gets from one place to another. Speed is calculated by taking the distance traveled by the time taken. Speed = distance/time V = d/t

4. Distance Verses Displacement Distance is how far an object has moved from it’s original starting point. Displacement is the distance and direction of an object’s change in position from the starting point. http://www.absorblearning.com/media/item.action?quick=4nhttp://www.absorblearning.com/media/item.action?quick=4n

5. Forms of the Speed Equation Equation Gives you…If you know… v = d/tSpeedtime and distance d = vtDistancespeed and time t = d/vtimedistance and speed

6. Velocity Velocity is the quantity describing both speed and direction. Velocity = distance/time in a specific direction Velocity can change without the speed changing.

7. What is the velocity of a car that traveled a total of 70 kilometers south in 1.2 hours? What is the speed of a jet plane that travels 528 meters in 4 seconds?

8. A car is traveling 110 km/hr. How many hours will it take to cover a distance of 725 km? How many seconds will it take for a satellite to travel 450,000 m at a rate of 120 m/s?

9. How far, in meters, will you travel in 180 seconds running at a rate of 6 m/s? The earth travels at 68,000 miles/hour as it moves around the sun. How many miles does the earth travel in one trip around the sun (8760 hrs)?

11. Acceleration Acceleration is the rate of change in velocity. If either speed or direction changes, the velocity will change. Acceleration can occur through a change in speed or change in direction.

12. Acceleration (2) Acceleration can be positive or negative. When a car comes to a stop, this is called deceleration. The speed is decreasing, so the acceleration is negative. The speed is increasing, so the acceleration is positive.

13. Acceleration Formula a = (v 2 – v 1 )/time or a = (v f – v i )/time v 2 or v f is the final velocity v 1 or v i is the beginning or initial velocity.

14. What Does an Acceleration Value Tell You? If the acceleration is small, that means the speed is increasing very gradually. If the acceleration has a greater value, the object is speeding up more rapidly. If an object has zero acceleration, then it is traveling at a constant speed in one direction.

15. Acceleration Practice Problem If a car is traveling at a speed of 40 m/s and stops within 2.5 s, what is the car’s acceleration? V 1 = V 2 = T= A=

16. Acceleration Practice Problem Susan stops a ball and 2 seconds later the ball has a speed of 20 m/s. What is the ball’s acceleration? V 1 = V 2 = T= A=

17. Acceleration Practice Problem John goes over the top of a hill at a speed of 4 m/s while on his bike. Four seconds later his speed is 24 m/s. What is his acceleration? V 1 = V 2 = T= A=

18. Acceleration Practice Problem Sally places a ball at the top of a ramp and lets it go. Four seconds later the ball is moving at a speed of 2.4 m/s. What is the acceleration? V 1 = V 2 = T= A=

19. Acceleration Practice Problem Dave is traveling at 20 m/s in a car when it hits a tree. Dave comes to a complete stop in 4 seconds. What is his acceleration? V 1 = V 2 = T= A=

20. Acceleration Practice Problem A cart rolling down an incline for 5.0 seconds has an acceleration of 4.0 m/s 2. If the cart has a beginning speed of 2.0 m/s, what is the final speed? V 1 = V 2 = T= A=