Warmup 9/8/15
During an earthquake, there are
a lot of ways that the ground
can move. One example
is shown at right. If it was up to
you, what would you call this
kind of force, where one thing
slides past another?
Objective
To learn about the different
kinds of forces that affect
matter
Tonight’s Homework
Read sections 2.5 and 2.6
Do p 33: 1, 2, 3
Notes on Forces
There are 2 main types of forces: contact forces and
field forces. Contact forces are where we have two
things that make contact with each other. Usually,
this is two things that push, pull, or twist on each
other in different ways.
Notes on Forces
There are 2 main types of forces: contact forces and
field forces. Contact forces are where we have two
things that make contact with each other. Usually,
this is two things that push, pull, or twist on each
other in different ways.
Compression
In this type, our two objects are trying
to push into each other. Usually,
something ends up squished or crushed.
Shear
In this type, our objects are sliding
past each other. When something snaps,
we’re getting a shear force.
Notes on Forces
Tension
In tension, we have two objects that are
stuck together but something is trying
to pull them apart. A rope stretching
is a good example of tension.
Torsion
This is a twisting force. In this, our
two objects are trying to spin around
each other and change places.
Notes on Forces
Field forces are forces that act without having to
touch.
Notes on Forces
Field forces are forces that act without having to
touch.
Gravity
Gravity is the force that pulls all things with mass
towards other things with mass.
Electricity
This is the force that controls how electrons go
around atoms and how electricity flows.
Magnetism
This is a force similar to electricity that controls how
magnets react to each other.
Examples of Forces
Your job for the rest of class is to do the following:
Come up with 3 examples of places where you’d see each
of the 4 kinds of contact forces: compression, shear,
tension, and torsion. You’ll turn this in when done.
If you finish early, you have the rest of class as worktime
to catch up on whatever you need for this class.
Exit Question
What type of contact force
destroyed these cars?
Compression
Shear
Tension
Torsion
All of the above
None of the above