NS3310 Dr. Hoge

Cartoon Laws of Physics Law I Any body suspended in space will remain in space until made aware of its situation. Law II Any body in motion will tend to remain in motion until solid matter intervenes suddenly. Law III Any body passing through solid matter will leave a perforation conforming to its perimeter. Law IV The time required for an object to fall twenty stories is greater than or equal to the time it takes for whoever knocked it off the ledge to spiral down twenty flights to attempt to capture it unbroken. Law V All principles of gravity are negated by fear. Law VI As speed increases, objects can be in several places at once. Law VII Certain bodies can pass through solid walls painted to resemble tunnel entrances; others cannot. Law VIII Any violent rearrangement of feline matter is impermanent. Corollary: A cat will assume the shape of its container. This is also true for ducks, Martians, Roosters, and many other cartoon characters. Law IX Everything falls faster than an anvil. Law X For every vengeance there is an equal and opposite re-vengeance.

Momentum p = mv Clowns on Ice Life Preserver Problem Momentum is Conserved Collisions Elastic Inelastic

Momentum Problems Why are Boxing Gloves Safer than Bare Hands? How Can Cats Survive Long Falls? Bed of Nails, Anyone? What should you do if you are trapped in a falling elevator?

Impulse Impulse = Ft Impulse =  p (Impulse equals change in Momentum) Why is it easier to accelerate a soccer ball than a bowling ball? Can you push your van from the inside? Why is it better to push your stalled van than to hit it?

Work W = Fd Force is measured in Newtons (N), or Pounds (lb) Distance is measured in meters (m), or feet (ft) Work is measured in Joules (J, which = 1 Nm), or Foot-Pounds (ft-lbs) HINT: Don’t forget the units! Without units, you don’t have a complete answer. And, if you don’t have the right units at the end, you did something wrong.

Power Power = W / t Work is measured in Joules (J), or Foot-Pounds (ft- lbs) Time is measured in hours or seconds (hr, s) Power in measured in J/t (Joules per second) or horsepower (550 ft-lbs/s)

Work Problems How do simple machines reduce the amount of work? How do gears work? How do engines have horsepower?

Simple Machines Levers Pulleys Inclined Planes Wedges Screws

Fun with Physics Roller Coaster Physics The Physics of Baseball NASCAR Physics Physics of Martial Arts Movie Physics Physics of Superheroes