Time and Date Stamps (logged): 03:47:11 08-29-2008 ¯²Ÿ³¶Ÿ°°¯·Ÿ±¸Ÿ±¯¯· Physics II

Principles of Physics (Phy 122) Test_Set_5

Completely document your work and your reasoning.

You will be graded on your documentation, your reasoning, and the correctness of your conclusions.

** Write clearly in dark pencil or ink, on one side of the paper only. **

Date and Time are 02-15-2001 19:28:18

Signed by Learning Lab Attendant: ______________________

Date and Time: ______________________

Attendant:

Test is to be taken without reference to text or outside notes.

Calculator is allowed.

No time limit but test is to be taken in one sitting.

Please place test in Dave Smith's folder when completed.

Student:

Completely document your work.

Undocumented and unjustified answers may be counted wrong.

Besides undocument and unjustified answers, if wrong, never get partial credit.

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Problem Number 1

At a certain depth a `plug' of exiting water, .04 meters long, initially at rest and with cross-sectional area .00079 m^2, as it is forced out of a container by gauge pressure 35000 N/m^2.  Use work and energy considerations to find the velocity of the exiting water.

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Problem Number 2

Water is under pressure 90000 N/m^2 in a tube whose radius is .14 m.  What is the pressure after the tube narrows to radius .07 m, if water in the .14 m part of the tube flows at 2.1 m/s?

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Problem Number 3

It requires 7.6 Joules of energy to increase the temperature of 5 kg of a certain substance by 19 degrees Celsius. What is the specific heat of the substance? 

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Problem Number 4

The velocity of a confined fluid of density 1000 kg/m^3 changes from 6 m/s to 5.9 m/s with no change in altitude, and with no dissipative forces at work.  What will be the change in pressure?

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Problem Number 5

What is the average force associated with 5.6 * 10^6 particles, each of mass 2.494251E-07 Kg, colliding elastically with a wall at a velocity of 105.4 m/s, with directions randomly distributed in 3 dimensions? Assume that the wall is one of the walls of a rectangular 'box', separated by 46 meters from the wall parallel to it.

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Problem Number 6

Suppose that a closed system with constant number of moles of a gas and a constant pressure has volume 262.7 liters when the temperature is 265 Celsius. What Celsius temperature will result in a volume of 307.2 liters?

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Problem Number 7

What is the average temperature gradient (i.e., the rate of temperature change with respect to distance) from inside to outside through a wall whose area is 12 m^2, whose thickness is everywhere .36 m and whose inside and outside surfaces are at 164 and 9 Celsius?

What would be the gradient if the temperature difference increased by a factor of 1.452?

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Problem Number 8

At a depth of 7.1 meters in water, how much force will there be on a rectangle whose dimensions are 7 m by 4.1 m?

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Problem Number 9

A system consisting of a cylinder full of gas, sealed by a piston, is alternately loaded, heated, unloaded and then cooled back to its original state.

If 475.3 Joules of work are done, and if 494.7 Joules of thermal energy are taken out or lost during cooling and other processes, then what is the efficiency of the system?