1 / 18

Motion and Newton’s first law What is a force? Identifying forces Newton’s second law

Chapter 4 Forces and Newton’s Laws of Motion. Motion and Newton’s first law What is a force? Identifying forces Newton’s second law Free-body diagrams Newton’s third law. Topics:. Sample question:.

jaeger
Download Presentation

Motion and Newton’s first law What is a force? Identifying forces Newton’s second law

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. Chapter 4 Forces and Newton’s Laws of Motion • Motion and Newton’s first law • What is a force? • Identifying forces • Newton’s second law • Free-body diagrams • Newton’s third law Topics: Sample question: These ice boats sail across the ice at great speeds. What gets the boats moving in the first place? What keeps them from going even faster? Slide 4-1

  2. Example • An elevator, lifted by a cable, is going up at a steady speed. • Identify the forces acting on the elevator. • Is FT,cable => elevator greater than (A), equal to (B), or less than Fg,Earth => elevator(C)? Or is there not enough information to tell (D)? Slide 4-23

  3. Checking Understanding • 10-year-old Sarah stands on a skateboard. Her older brother Jack starts pushing her backward and she starts speeding up. The force of Jack on Sarah is • greater than the force of Sarah on Jack. • equal to than the force of Sarah on Jack. • less than the force of Sarah on Jack. Slide 4-27

  4. Answer • 10-year-old Sarah stands on a skateboard. Her older brother Jack starts pushing her backward and she starts speeding up. The force of Jack on Sarah is • equal to than the force of Sarah on Jack. Slide 4-28

  5. A Short Catalog of Forces: Weight w  Slide 4-12

  6. Spring Force Fsp Slide 4-13

  7. Tension Force Slide 4-14

  8. Normal Force Slide 4-15

  9. Friction fk and Slide 4-16

  10. Drag and Thrust Slide 4-17

  11. Example 1 A block is dragged uphill by a rope. Identify all forces acting on the block. Slide 4-19

  12. T2 30 T1 Example 2 • The cable at left exerts a -30 N force. • Write the equation for the sum of the forces in the x-direction. What is the value of FT2? • Write the equation for the sum of the forces in the y-direction. What is the force of gravity acting on the ball? Slide 4-20

  13. Exercise A ball, hanging from the ceiling by a string, is pulled back and released. Identify the forces acting on it just after its release. Slide 4-21

  14. Newton’s Second Law Slide 4-22

  15. Newton 2 Demonstrations Slide 4-19

  16. Newton’s Third Law Slide 4-25

  17. Newton’s 3rd Law Demonstrations Slide 4-19

  18. Newton’s Laws of Motion Newton 0th Law Objects are dumb - They have no memory of the past and cannot predict the future. Objects only know what is acting directly on them right now Newton's 1st Law An object that is at rest will remain at rest and an object that is moving will continue to move in a straight line with constant speed, if and only if the sum of the forces acting on that object is zero. Newton's 2nd Law acceleration of an object = sum of forces acting on that object / the mass of the object Newton's 3rd Law Recall that a force is an interaction between two objects. If object A exerts a force on object B then object B exerts a force on object that is in the opposite direction, equal in magnitude, and of the same type. Slide 4-19

More Related