physics 151 week 9 day 2
Download
Skip this Video
Download Presentation
Physics 151 Week 9 Day 2

Loading in 2 Seconds...

play fullscreen
1 / 9

Physics 151 Week 9 Day 2 - PowerPoint PPT Presentation


  • 85 Views
  • Uploaded on

Physics 151 Week 9 Day 2. Topics: Forces, Apparent Weight, & Friction Applying Newton ’ s 2nd Law Apparent Weight Friction Static Friction Kinetic Friction Coefficient of Friction Normal forces and Friction Applications . General Force Model. Newton 0th Law

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Physics 151 Week 9 Day 2' - nero-ryan


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
physics 151 week 9 day 2

Physics 151 Week 9 Day 2

Topics: Forces, Apparent Weight, & Friction

Applying Newton’s 2nd Law

Apparent Weight

Friction

Static Friction

Kinetic Friction

Coefficient of Friction

Normal forces and Friction

Applications

slide2

General Force Model

  • 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 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.
  • Visualizations:
    • Force Diagrams
    • System Schema
slide3

Net Force Model

Newton\'s 2nd Law

acceleration of an object = sum of forces acting on that object / the mass of the object

Note: Solve Newton’s 2nd Law equations in component form

Visualizations:

Force Diagram

System Schema

Motion visualizations as needed

Remainder of week:

Friction Model

Apparent Weight

Slide 4-19

slide4

Example Problem

A sled with a mass of 20 kg slides along frictionless ice at 4.5 m/s. It then crosses a rough patch of snow which exerts a friction force of 12 N. How far does it slide on the snow before coming to rest?

Slide 5-21

slide5

Example Problem

A 75 kg skier starts down a 50-m-high, 10° slope on frictionless skis. What is his speed at the bottom?

Slide 5-27

slide6

Brainstorm: What do we know about Friction Force?

Force created by the surface – against the motion

It is parallel to the surface

slide7

Static & Kinetic Friction - Part IDemonstration

Explain the graph, i.e. why does it look this way?

Slide 4-19

slide8

Static & Kinetic Friction - Part III

Below is graph of the friction force exerted by the table on the box. 


Label times a-f that match the free-body diagrams in the previous problem.

If the mass of the box is 3.0 kg, the maximum Ffs is 10 N, and Ffk has an average of 6.0 N, find the coefficients of static and kinetic friction.

Slide 4-19

slide9

Coefficients of Friction – Do as warm-up for Wed.

What can you deduce/generalize about friction forces from this table?

Describe 3-4 real world situations that can be explained by this table

Slide 4-19

ad