1. Motion Distance Displacement Speed: average and instantaneous Velocity Acceleration

2. Distance and Displacement Starting from origin, O a person walks 90-m east, then turns around and walks 40-m west. Q: What is the total walked distance? A: 130-m Q: What is the displacement? A: 50-m, due east.

3. Speed Average and Instantaneous

4. Let’s Go to Myrtle Beach

5. Average Speed Average speed equals the distance traveled divided by the time of travel. Speed is a scalar quantity. Unit of speed: m/s

6. Instantaneous Speed

7. Scalars and Vectors Many physical quantities are used in physics, which are divided into scalars and vectors. A scalar quantity is one that can be described by a single number (including any units) giving its size or magnitude. Examples: Time interval, distance, speed, volume, mass, temperature, and density. A quantity that deals inherently with both magnitude and direction is called a vector quantity. Examples: Force, weight, velocity, and displacement.

8. Scalars and Vectors ScalarVector DistanceDisplacement SpeedVelocity MassWeight

9. Vector Illustration The length of the vector arrow is proportional to the magnitude of the vector and the arrow represents the direction. In the text, bold face is used for vectors and italics is used for scalars. When hand written an arrow is placed above the symbol. Consider the following displacement vector of a car:

10. Velocity Velocity is a vector. Velocity = Speed + Direction

11. Acceleration Have you experienced acceleration? Acceleration is the rate at which velocity changes. Acceleration is a vector quantity. Unit of acceleration: m/s 2

12. Acceleration

13. Acceleration can be Positive or Negative Negative

14. Can a Car Be Accelerating When Its Speed Is Constant?

15. Acceleration of a Sports Car http://www.cars.com/go/crp/buyingGuides/Story.jsp?section=Spor ts&story=sportsQuickest&subject=stories&referer=&year=2005http://www.cars.com/go/crp/buyingGuides/Story.jsp?section=Spor ts&story=sportsQuickest&subject=stories&referer=&year=2005

16. Free Fall Acceleration due to gravity affects the velocity of an object as it falls.

17. Apparent Weightlessness

18. Space Station http://spaceflight.nasa.gov/realdata/tracking/ Universal gravitational constant = G = 6.673 x 10 -11 N.m 2 /kg 2 Mass of Earth = M = 5.98 x 10 24 Kg Radius of Earth = R = 6380 km Height of Mt. Everest = 8.85 km Altitude (km) a g (m/s^2) Altitude Example 09.83Mean Earth Surface 8.89.80Mt. Everest 36.69.71Highest crewed balloon 4008.70Space Shuttle Orbit 35,7000.225Comm. Satellite