Spectacular Science
Presentation by Daniel Riedinger
Teacher Reseda HS Police Magnet
Friction
• What is it• Opposes motion• empirical laws of
friction first investigated more than five hundred years ago by Leonardo da Vinci
Types of Friction
• Sliding Friction: friction produced when two solid objects slide over each other.
• Rolling Friction: friction produced when an object rolls over a surface.
• Fluid Friction: friction produced when an object moves through a fluid.
Is Friction a Good Thing or a Bad
Thing?
What Affects Friction
• Surface type and weight• Force from friction/weight of object =• A constant number• f / N = µ the coefficient of friction• f = µ N• What about surface area?• Friction is independent of surface area
Tornadoes
• Whirling funnel shaped cyclone
• Common on the great plains during spring
• Up to 300 mph winds
Tornadoes
• Tornados are the smallest, most violent, and shortest lived severe storm.
• When a thunderstorm encounters high altitude, horizontal winds, a tornado can be formed.
• These winds can cause the rising air in the thunderstorm to start rotating.
• A narrow funnel shaped, rapidly spinning extension may develop in the cloud.
• Tornados generally cover a path of about 100m wide, destroying everything in their path.
• The tremendous speeds of the winds in a tornado are responsible for the destruction they cause.
• The falling of debris when a home is destroyed or being struck by flying objects causes most deaths and injuries.
• It is very important to find cover in a low place.
Worst Tornado
• March 18, 1925
• Started in Missouri, ended in Indiana• Forward speed was a record setting
73mph • For over 100 miles, the path was
about three quarters of a mile wide• 2027 injured, 695 dead
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