Pressure clicker question (Nov. 2): Points A and B are on the bottom of a container of water, at the same depth below the surface of the water. The pressure is higher at point A.point A B.point B C.Pressures are equal at A and B A B Pascal’s principle

Archimedes’ clicker question (Nov. 2): A solid metal cylinder is suspended from a spring scale, which reads 20 N. The cylinder is lowered into water, so it is submerged. The reading on the scale is A.> 20 N B.= 20 N C.< 20 N

12/6/2015A.PH 105 PH /4 ----Monday, Nov. 5, 2007 Homework: PS 11 (Ch. 11) due Wednesday (Nov. 7) PS 12, Chapter 14, is due Nov 14. Chapter 14: Fluids (review) Pressure = Force/Area Pascal’s principle P =  g h Archimedes’ Principle: Buoyant force = weight of displaced fluid. Equation of continuity: A 1 v 1 = A 2 v 2

Example: Garden hose has r = 1 cm, narrowing to r = 0.5 cm at nozzle. If nozzle velocity is 10 m/s, what is the water velocity in the hose? A.Equation of continuity: A 1 v 1 = A 2 v 2 Bernoulli’s Equation: p+½  v 2 +  g y = constant  Torricelli’s theorem: v of water stream from hole in container.

Clicker question (Nov. 5): The New Orleans superdome has air velocity v =0 below the roof, but v = 100 m/s above the roof. The pressure will be larger A.below the roof B.above the roof C.same above and below v = 100 m/s v’ ~ 0 p+½  v 2 = p’+½  v’ 2

Clicker question #2 (Nov. 5): The New Orleans superdome still has air velocity v =0 below the roof, but v = 100 m/s above the roof. The pressure pressure difference p’-p is (in N/m 2 ) A.below the roof B.above the roof C.same above and below v = 100 m/s v’ ~ 0 p+½  v 2 = p’+½  v’ 2  = 1.2 m/kg 2

Clicker question #2 (Nov. 5, not done): The New Orleans superdome still has air velocity v =0 below the roof, and v = 100 m/s above the roof. The pressure difference p’-p is (in N/m 2 ) v = 100 m/s v’ ~ 0 p+½  v 2 = p’+½  v’ 2  = 1.2 m/kg 2

Bernoulli’s Equation: p+½  v 2 +  g y = constant  Torricelli’s theorem: v of water stream from hole in container v 2 = 2 g h (same as falling object)! Chapter 15: Oscillations Mass on spring: GUESS x = A sin (  t)  2 = k / m