NonTerrestrial Transportation Boats Rafts Sailboats Ships Hydrofoils Aircraft

Non-Terrestrial Transportation Boats Rafts, Sailboats, Ships, & Hydrofoils Aircraft Planes, Passenger Jets, Helicopters 1

Blowing on paper Buoyancy Kit (tin foil, washers) Cartesian Diver Blower and Ping Pong Sailboat and Track Spoon Fairy 2

Early Boats Hollowed out logs n Reed rafts n Pirogue www. tulsaweb. com Pronounced: pē-rōg Redwood Grove, Los Altos

Overcoming Gravity acts the same on all objects - exerts greater forces on larger masses and smaller forces on less massive objects such that the downward acceleration is the same for all objects 4

Objects suspended in fluids (air and water) Buoyancy Force counteracts the weight of the object: mg = Fbuoyancy 5

Fluids exert pressure Atmosphere at sea level exerts 14. 7 psi (lbs/in 2) in all directions due to gravity pulling down on the column of air above our heads. Pressure decreases at higher elevations. 6

Water not moving 7

Water not moving Forces due to pressure = Net Buoyant Force = Weight of water 8

Replace water with object Forces due to pressure have not changed Net Buoyant Force = Weight of water displaced 9

If weight of object < Fb (object rises) If weight of object > Fb (object sinks) 10

Archimedes and Buoyancy i. e. some things fall “up”! n Before discovering the Lever and the Screw for lifting water, Archimedes discovered buoyancy. Archimedes Principle states that the buoyant force on a submerged object is equal to the weight of the fluid that is displaced by the object.

This Concept is best seen with Hot Air or Helium Balloons The balloon rises because the weight of the balloon, gondola, and the internal gas is less than the air displaced by the balloon. This is called upthrust.

What would you weigh if fully submerged in water? n (Your weight – the wt. of the water displaced) What figure weighs more in the pool? 100 lbs.

Cartesian Diver n n By squeezing the bottle the pressure increases. The air in the condiment package compresses, lowering its volume. Less water is displaced if the condiment package is compressed, making the package less buoyant. http: //www. sciencetoymaker. org/diver

Water going vessels can be very heavy as long as they displace enough water n The vessel will float if it displaces water equal to the weight of the boat (including cargo). It must do this without taking water over the sides The Ice Breaker – has an armored steel hull www. tq-international. co

Materials that are denser than water such as steel can be made to float on water as long as the steel object can displace an amount of water equal to its weight. Many Civil Engineering programs build and compete in a Concrete Canoe event. http: //uwnews. org

Three similar sized pieces of tin foil One floats n One sinks n One appears suspended n What’s the difference between them?

The Accepted Anthropological Map Showing Migration of Homo Sapiens

Drawbacks with Exploration Over Land Restricted by Land (a small percentage of our planet – 29%) n Terrain constraints (mountains, deserts, rivers) n Enemies n Reliance on stock animals n High maintenance wagons n

Benefits and Challenges with Exploration over Water n n n Greater mobility Riskier Powered by Wind Density of salt water allows large vessels to float Navigation is difficult Usually capital Intensive

Propelling Boats and Aircraft Oars – for every force there is an equal and opposite force. n Action-Reaction n Sails n Propellers n Airfoils n

Propellers are Fans 22

Helicopters http: //science. howstuffworks. com/helicopter. htm

Wings n Airplane wings exert a downward force on the air. The air pushes up on the wing with an equal force. http: //www. seed. slb. com/en/scictr/watch/sailing/index. htm Umbrella Animation

Airfoil n A surface designed to produce lift from the movement of air over it. http: //www. aircommand. com It is the Coanda Effect that gives the fluid the tendency to follow the contour of the upper surface rather than traveling in a straight line. Wikipedia

The Coanda Effect Fluid flow Newton’s 3 rd law indicates that the fluid forces the object to the right as it travels along the surface to the left. http: //www. allstar. fiu. edu/AERO/airflylvl 3. htm

Getting Lift with Airplanes LIFT: Vertical force DRAG: Horizontal force http: //howthingswork. virginia. edu/airplanes. html A really good explanation. http: //www. allstar. fiu. edu/AERO/airflylvl 3. htm A much more detailed explanation. Lift comes from the air around the wing that is diverted downward.

Would this Airfoil Produce Lift? Yes, but drag force is excessive. 28

The four forces Lift n Drag n Weight n Thrust n http: //www. eng. fsu. edu/~ugartjo/Drag. htm

Sailing on a Tack (against the wind) http: //sail-boats. suite 101. com

Sailboat Demonstration n Blow air at a 450 angle of attack to show that the pulling force is greater than the pushing force, producing a net force in the windward direction http: //www. seed. slb. com/en/scictr/watch/sailing/index. htm Good Animation of Sails and angle of attack

As air moves faster its pressure decreases. n n Throwing a curve ball as demonstrated by a good pitcher Shower Curtain problem Blowing air across paper to make is rise Blow Dryer and ping pong trick http: //wings. avkids. com/Book/Sports/instructor/curveball-01. htm

Propellers have the shape of airfoils http: //www. athropolis. com/

Forces from Ailerons and Elevators A lowered Aileron produces Lift, while a raised Aileron reduces Lift. The two Ailerons make the aircraft roll. n Elevators are at the rear and control the pitch. n http: //en. wikipedia. org/wiki/Aileron A good animation here. http: //en. wikipedia. org/wiki/Elevator_(aircraft

Plane Components http: //www. centennialofflight. gov/about/index. htm

Hydrofoil n Hydrofoils are used to ferry people across the English Channel. The hydrofoils produce lift, raising the boat out of the water. Once above the surface, the boat can skim over the top as it is relatively unaffected by waves. www. maths. otago. ac. nz Surface Piercing Foil follows the contours of the waves.

The hydrofoil in inherently stable because when it leans to one side more of the foil on the low side is submerged, increasing the lift on that side. Thus the boat ‘rights’ itself. Also this hydrofoil follows the contours of the waves. When it travels into a wave, more the foil goes underwater giving the boat greater lift. When it travels out of a wave, less of the foil is underwater, therefore the lift decreases. http: //www. hydrofoil. com/hitest/reference. html

How do spacecraft maneuver in the absence of air? n n Newton’s 3 rd Law High Pressure Fuel Exerts a force on one side of rocket while being released out the back. 38