Chapter 9

The same force is applied to two cylinders that contain air. One has a piston with a large area, and the other has a piston with a small area. In which, if either, cylinder will the pressure be greater?

the small area cylinder

If you filled an airtight balloon at the top of a mountain, how, if at all, would the balloon change as you descended the mountain?

It would contract.

If the output piston in a hydraulic pump exerts a greater force than one applied to the input piston, how is the pressure at the output piston compared with the input piston?

the same

A large bird lands on a rowboat that is floating in a swimming pool. How will the water level in the pool change when the bird lands on the boat?

it will increase

The lift on airplane wings is explained by

Bernoulli's principle.

A force of 87 N pushes down on the movable piston of a closed cylinder containing a gas. The piston’s area is 0.4 m2. What is the pressure produced in the gas?

217\.5 Pa

With the temperature held constant, the pressure of a gas in a cylinder with a movable piston is increased from 5 kPa to 40 kPa. The initial volume of the gas in the cylinder is 0.75 m3. What is the final volume of the gas after the pressure is increased?

.0938 m^3

In a hydraulic system, a force of 555 N is exerted on a piston with an area of 0.002 m2. The load-bearing piston in the system has an area of 0.3 m2.

a) Calculate in kPa the pressure in the hydraulic fluid induced by the applied pressure.

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b) What is the magnitude of the force exerted on the load-bearing piston by the hydraulic fluid? (___ x 10^4)

a) 277.5 kPa

b) 8.325 x 10^4

A stream moving with a speed of 7.3 m/s reaches a point where the cross-sectional area of the stream decreases to one half of the original area. What is the speed of the water in this narrowed portion of the stream?

14\.6 m/s

A rock with a volume of 1.5 m3 is fully submerged in water having a density of 1000 kg/m3. What is the buoyant force acting on the rock (given: *g* = 9.8 m/s2)? ( ___ x 10^3)

14\.7 x 10^3

Is it possible for a 100-lb woman to exert a greater pressure on the ground than a 250-lb man?

yes

A 270-lb man supports all of his weight on a snowshoe with an area of 225 in2. What is the pressure exerted on the snow (in pounds per square inch)?

1\.2 psi

An airplane wing with an average surface area of 8 m2 experiences a lift force of 74000 N. What is the difference in air pressure, on an average, between the bottom and the top of the wing?

9250 Pa

fA clown at the circus blows up a balloon with helium. This balloon will not float to the ceiling unless

the balloon and the helium it contains weigh less than the air displaced by the balloon.

A certain boat displaces a volume of 9.6 m3 of water. (The density of water is 1000 kg/m3.)

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 a) Determine the mass of the water displaced by the boat.

b)Calculate the buoyant force acting on the boat in kN (given: *g* = 9.8 m/s2).

a) 9600 kg

b) 94.08 kN

A rectangular block is suspended by a string in a beaker of water so that the block is completely surrounded by water. How does the water pressure at the bottom of the block compare with the water pressure at the top of the block?

it’s greater at the bottom

archamides principle

boyancy/ float

object floating=weight=weight fluid

stationary fluid

density(depth) or W/A

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boyles law

P1V1=P2V2

pascal’s principle

F1/A1=F2/A2

positions and stationary fluid

bernoulli’s principle

fluid motion

P+1/2pv^2

object has a greater density than the liquid

it will sink

object has the same density has the liquid

it will float, be stationary

object has a smaller density than the liquid

it will float

what’s an example of boyancy?

hurricane and all the windows are closed, they roof will blow off

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broyonlys law says open window needs to be open so this doesn’t occur

atmospheric pressure

1 atm

760 tores

14\.6 lbs squ inch