Sign In | Subscribe

Enter your Sign on user name and password.

Forgot password?
  • Follow us on:
Start learning today, and be successful in your academic & professional career. Start Today!
Loading video...
This is a quick preview of the lesson. For full access, please Log In or Sign up.
For more information, please see full course syllabus of AP Physics B
  • Discussion

  • Study Guides

  • Download Lecture Slides

  • Table of Contents

  • Related Books & Services

Start Learning Now

Our free lessons will get you started (Adobe Flash® required).
Get immediate access to our entire library.

Sign up for

Membership Overview

  • Unlimited access to our entire library of courses.
  • Search and jump to exactly what you want to learn.
  • *Ask questions and get answers from the community and our teachers!
  • Practice questions with step-by-step solutions.
  • Download lesson files for programming and software training practice.
  • Track your course viewing progress.
  • Download lecture slides for taking notes.
  • Learn at your own pace... anytime, anywhere!

Accelerating Frames

  • A scale reads the value of the normal force it exerts.
  • If you stand on a scale in an accelerating elevator, the scale will show a weight different than your actual weight: Apparent weight = m(g + a).
  • In an accelerating train, a pendulum will not hang vertically, but rather at an angle with the vertical: tan(theta) = a/g.

Accelerating Frames

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • What Does a Scale Measure 0:11
    • Example: Elevator on a Scale
    • Normal Force
  • Apparent Weight in an Elevator 7:42
    • Example: Elevator Starts Moving Upwards
    • Net Force (Newton's Second Law)
    • Apparent Weight
  • Pendulum in an Accelerating Train 15:58
    • Example: Object Hanging on the Ceiling of a Train
    • Angle In terms of Increased Acceleration
  • Mass and Spring in an Accelerating Truck 23:40
    • Example: Spring on a Stationary Truck
    • Surface of Truck is Frictionless
    • Spring is Stretched by distance X
  • Cup of Coffee 29:55
    • Example: Moving Train and Stationary Objects inside Train
    • Train Moving With Acceleration A
    • Force of Static Friction Acting on Cup
  • Extra Example 1: Train Slows with Pendulum
  • Extra Example 2: Person in Elevator Releases Object
  • Extra Example 3: Hanging Object in Elevator