1 / 15

One dimensional kinematics

One dimensional kinematics. Speed—how fast an object is moving. Units—miles per hour, meters per second, etc. Constant speed—speed that does not change. Average speed—total distance covered divided by the total time it takes. Instantaneous speed—speed that occurs at a single point in time.

griffith-parry
Download Presentation

One dimensional kinematics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. One dimensional kinematics • Speed—how fast an object is moving. • Units—miles per hour, meters per second, etc. • Constant speed—speed that does not change. • Average speed—total distance covered divided by the total time it takes. • Instantaneous speed—speed that occurs at a single point in time.

  2. One dimensional kinematics • Velocity—speed in a given direction. • Speed is 20 m/s, velocity is 20 m/s to the west. • Vector—an arrow that represents the magnitude and direction of a quantity. • Vector quantities—are those that need magnitude and direction to specify the quantity completely. • A velocity of 50 miles per hour north, a weight of 150 pounds downward, a force of 50 pounds to the left.

  3. One dimensional kinematics • Scalar quantities—are those that do not need a direction. • Scalar quantities are mass, volume, time, length, etc.

  4. One dimensional kinematics • Acceleration—the rate at which velocity changes with time. • Starting at 0 m/s and increasing velocity by 2 m/s means an acceleration of 2 m/s/s or 2 m/s2. • If velocity increases from 10 to 40 m/s in 3 seconds, acceleration is 30/3 or 10 m/s/s. • Acceleration also occurs when direction changes. You feel this acceleration when driving around a curve.

  5. Left hand page assignment • Quick write: Describe how speed, velocity, and acceleration are related using vector, magnitude, direction. • Think, pair, share. Compare your response with elbow partner. • Revise your quick write to add anything you may have forgotten. • Comparison matrix for speed-velocity, and velocity-acceleration.

  6. Graphing motion • Graph d vs t (none, positive/negative velocity) • +10 • 0 -10 Describe these in the graphs.

  7. Graphing motion • Graph v vs t (none, positive/negative velocity) • +10 • 0 -10 Describe these in the graphs.

  8. Graphing motion • Graph v vs t and d vs t for accelerating motion • +10 • 0 -10 Describe these in the graphs.

  9. Left hand page • Sketch a distance-time graph showing an object that starts from a position 150 meters left of the origin, moves to the right 200 meters in 40 seconds, stops for 5 seconds, moves to the right another 200 meters in 80 seconds and then returns to origin in 125 seconds. HINT: Calculate the total distance and total time in order to create the axes. • Determine the speed in each of the 3 segments. • Compare with your neighbor and revise as needed.

  10. Generating graphs from acceleration • Begin with velocity of 0 and acceleration of 10m/s/s and calculate the velocity for times of 1-5 seconds. • Then calculate the distances covered by each of these velocities. • This is an approximation of free fall due to gravity on earth at the surface. • Deriving equations of motion.

  11. Rising and falling objects • Objects rise and their velocity decreases to 0 then increases as it falls to earth. • Start with upward velocity of 30 m/s and approximate acceleration of 10 m/s/s. • Determine velocities and distances moved at whole number units of time.

  12. Practice calculations • Calculate the speed of an object that moves 3000 meters in 500 seconds. • How far does an object move in 12 seconds at a constant speed of 30 m/s? • A car travels 200 km in 6 hours, and then drives at 30 km/hr for 3 hours. Calculate the total distance travelled and the average speed of the car.

  13. Practice calculations • How far does a car travel in 3 hours and 15 minutes at an average speed of 45 m/s? • A car brakes from a speed of 50 m/s to a stop in 3 seconds. What is the magnitude of the acceleration? • A car starts at rest and accelerates at 12 m/s/s for 7 seconds. What is the new speed of the car? • How much time is needed for a ball to fall 200 meters?

  14. Practice calculations • What is the speed of a ball that has fallen for 3 seconds? • How far does a ball fall in 7 seconds of free fall? • A car travels at 50 km/hr for 380 minutes and then 60 m/s for 2 hours and 20 minutes. Calculate the distance moved and the average speed of the car.

  15. Left hand page • Quick write: What is DUFAS and how is it used to solve physics problems?

More Related