Transcript Frames of Reference

Inertial Frame of Reference
Discussion Outline
Created for CVCA Physics
By
Dick Heckathorn
28 November 2K + 4
Table of Contents
7
8
9
13
19
22
23
24
25
26
27
28
31
Laser Disk A: 48
Laser Disk B: 16, 17
Laser Disk: Frames of Reference
Some Questions
Laser Disk _: 12, 13, 14
Laser Disk _: 15, 16, 17, 18, 19
Student Analysis – Air Puck on Turntable
Power Point – Air Puck on Turntable
Riding the Rotor
Problem – Puck on Turntable
Laser Disk B: 24, 28, 29
Video – Rotor Geauga Lake
Summary
Have you ever, in a car wash…
jammed your foot on the brake
when you felt the car moving
and then felt foolish when it
wasn’t.
Have you ever, while stopped
at a stoplight …
jammed your foot on the
brake when you felt the car
moving and then felt foolish
when it wasn’t.
Have you ever …
thrown a ball up while riding
in a car or bus and wondered
how it looked from outside
the car or bus?
Have you ever...
?
Have you ever...
wished to be in a space
shuttle approaching a space
craft?
Cinema Classics Disk
Side A Chapter 48
Ball being dropped
from mast of ship
Cinema Classics Disk
Side B Chapter 16
Airplane and Flare
Side B Chapter 17
Snowmobile and Flare
Laser Disk
Frame of Reference
Is there an absolute frame of
reference?
What do you think?
Newton’s Law of motion holds
equally well whether reference
frame is not moving at all….
or moving with constant
velocity
These reference frames are
called inertial reference frames.
Newton’s laws work in an
inertial frame of reference.
They do not work in a noninertial (accelerated) frame of
reference.
When are you in an inertial
frame of reference?
If you are not moving or
moving with a constant
velocity.
Have you ever...
seen books sliding across
the car seat or the dash as
you turned a corner?
What is the force(s) acting on the
books?
There are none.
Why not?
We are using Newton’s laws in a
non-inertial (accelerated) frame.
If the reference frame is
accelerating…
Newton’s laws of motion do
not work.
If you placed a helium filled
balloon in a car or bus, what
would it do when:
you accelerated from rest?
you accelerated to a stop?
you turned a corner?
Transparency
Student Investigation
A Paper Model
Ball on Turntable
Power Point
Air Puck on Rotating Platform
Demonstration
Riding the Rotor
Power Point
Frame of Reference Problem
Cinema Classics Disk
Circular Motion
Side B Chapter 24
Ball and Merry-Go-Round
Side B Chapter 28
Rotor Ride
Side B Chapter 29
Dry Ice Puck on Turntable
Geauga Lake Video
The Rotor
Discuss:
Force(s) on ball rotating in a
circle
What is the outward (centriFugal)
force on the ball?
There is none.
Why not?
We are using Newton’s laws in a
non-inertial (accelerated) frame of
reference where they don’t work.
Summary:
Newton’s laws apply in inertial
reference frames, but they do
not apply in accelerated
reference frames.
Is the earth accelerating?
If so then why do Newton’s
laws work?
The expected differences are
too small to observe.
1905 Einstein:
a bodies mass will increase as
the velocity of the body
increases which is noticeable
only when the body approaches
the speed f light
w. ecp (207)
60 analyze
pendulum hung from roof of
car
Laser Disk Frames of Reference
Foucault Pendulum
20. Earth and Foucault Pendulum
21. Summary
That’s all folks!