Applications of Bernoullis Principle Demos Ping Pong Ball

Applications of Bernoulli’s Principle

Demo’s: Ping Pong Ball in funnel Ping Pong Ball in air stream Paper parallel paper http: //www. physics. ucla. edu/demoweb/demomanual/matter_and_thermodynamics/fluids/bernouli_demos. ht ml Note: With demos 1. 5 periods

slower speed faster speed more pressure less pressure

As the speed of a fluid increases, the pressure in the fluid decreases. P α 1/v

Bernoulli & Flight • Bernoulli’s Principle is what allows birds and planes to fly. • The secret behind flight is ‘under the

https: //www. youtube. com/watch? v=O 8 q. CA 2 m. Zv. VI

AIRFOIL On top: greater air speed and less air pressure On bottom: less air speed and more air pressure

v 2 v 1 Net force on wing?

LIFT THRUST DRAG GRAVITY

Spoiler – airfoil reversed less air speed more pressure greater air speed less pressure net force: downward

Racecar Spoiler provides better traction and avoids lift

Wind over a roof Patm = Proof + ½ 2 ρv v proof v=0 patm

slow air speed fast air speed

Curve Ball

Golf ball dimples

Winds over a mountain

Shower Curtain

Review Ping pong balls? Cardboard walls? Paper? Baseball?

Instability in passing – Trailers? Trains passing each other?

Atomizer – As air passes at top of tube, the pressure decreases and fluid is drawn up the tube.

http: //www. youtube. com/watch? v= 5 ltj. FEei 3 AI&feature=related

2009 Darwin Award

2009 Darwin Award (15 December 2009, Germany) A U 2 subway driver found a body laying besides the underground tracks in Berlin. Because there was no video surveillance camera at that location, it took police two days to reconstruct what had happened. Apparently Yasin A. , 22, was alone in the subway car when he decided it would be a brilliant idea to destroy one of the windows. By swinging feet forward from a handrail into the window, he not only managed to burst the glass but also succeeded in being sucked out of the moving train, and was left dead on the tracks. He was alone in the compartment at the time; if an observer had been present, perhaps the young underground rider would not have engaged in destructive nonsense that led to his senseless death.