Complete speed lab

1
Class Topics
Title General Science 9/12/07
Objectives

• To assess learning about speed.

• Complete speed lab
• Acceleration Calculations
• Nothing in the world can take the place of
  persistence. Talent will not nothing is more
  common than unsuccessful men with talent. Genius
  will not unrewarded genius is almost a proverb.
  Education will not the world is full of educated
  derelicts. Persistance and determination are
  omnipotent.
• Calvin Coolidge

Handouts
Saturday, October 03, 2009 1045 AM
2
Class Assignments
By When
What

• Acceleration quiz 9/12/07
• Read 356-362 9/13/07
• Due this class period
• Due next class period
• Due in the future

3
Postquiz activities

• Hand in quiz
• Read 356-362

4
Video

• Watch the Animal Planet video Noisiest Animals
• You will not complete this
• Have them fill out the review sheet while they
  watch (turn in when done)
• Stop the video with 5 minutes to go
• Handout homework due next class period
• Metric Mania

5
Force

• Force
• A push or pull that acts on an object
• Can cause an object to move or cause acceleration
  (changing speed or direction)
• Units of force
• Newtons
• Force that causes 1 kg to accelerate at 1m/s2

6
Force

• Representing force
• Arrows are used
• Figure 2 (p. 357)
• Note that the arrow in B is longer than than in A

7
Force

• Balanced forces
• No net movement
• Equal in both directions
• Unbalanced forces
• The force on one side is greater than that on the
  other side
• Causes acceleration

8
Friction

• A force that opposes the motion of objects that
  touch as they move past
• Necessary for life as we know it!
• Four main types
• Static
• Sliding
• Rolling
• Fluid

9
Static Friction

• Force that acts upon objects that are not moving
• Sliding a large rock
• Your shoe and the ground

10
Sliding friction

• A force that opposes the direction of motion of
  an object
• Less than static friction
• Takes less force to keep an object moving than it
  does to start it moving.

11
Rolling Friction

• 100-1000 times less force than static or sliding
  friction
• The object rolling and the surface upon which is
  rolls are both slightly bent out of shape
• Ball bearings

12
Fluid Friction

• The force that opposes the movement of an object
  through a fluid
• Water
• Mixture of gases
• Air resistance

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