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 BPascal’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

04/21/23 A. PH 105

PH 105-003/4 ----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/AreaPascal’s principle P = g h

Archimedes’ Principle: Buoyant force = weight of displaced fluid.

Equation of continuity: A1v1 = A2v2

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: A1v1 = A2v2

Bernoulli’s Equation: p+½v2 + g y = constantTorricelli’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+½v2 = p’+½v’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/m2)

A. below the roof

B. above the roof

C. same above and below

v = 100 m/s

v’ ~ 0

p+½v2 = p’+½v’2

= 1.2 m/kg2

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/m2)

6000

100

v = 100 m/s

v’ ~ 0

p+½v2 = p’+½v’2

= 1.2 m/kg2

Bernoulli’s Equation: p+½v2 + g y = constantTorricelli’s theorem:

v of water stream from hole in containerv2 = 2 g h (same as falling object)!

Chapter 15: OscillationsMass on spring:GUESS x = A sin ( t)

2 = k / m