# Recent content by qspartan570

1. ### (21-23) thermodynamics problem. Finding efficiency for the human body

Homework Statement While running up stairs at a (vertical) rate of 0.30 m/s, a man of 70 kg generates waste heat at a rate of 1300 J/s. What efficiency for the human body can you deduce from this? Homework Equations efficiency of heat...
2. ### (21-11) Thermodynamics problem help

Homework Statement The volume of a gas is decreased by a constant external pressure of 0.25 atm, changing from 2.0 liters to 0.50 liters. During this compression, 75 J of energy flows out of the gas. Find the work done by the gas and its change in internal energy. Homework Equations...
3. ### (19-74) Ideal gas problem

Homework Statement An oxygen cylinder for medical use contains oxygen at a pressure of 140 atm, at room temperature (20\circC). The cylinder measures 20 cm in diameter and 110 cm in length. How many kilograms of oxygen does this cylinder contain? What will be the volume of the oxygen if it...
4. ### Fnding the rms speed of hydrogen

Finding the rms speed of hydrogen Homework Statement The rms speed of nitrogen molecules in air at some temperature is 493 m/s. What is the rms speed of hydrogen molecules in air at some temperature? Homework Equations root-mean-square speedvrms= \sqrt{v2}=\sqrt{\frac{3kT}{m}}...
5. ### Fnding the rms speed of hydrogen

Homework Statement The rms speed of nitrogen molecules in air at some temperature is 493 m/s. What is the rms speed of hydrogen molecules in air at the same temperature? Homework Equations Vrms The Attempt at a Solution
6. ### Rising water level

Homework Statement Suppose that a zone of low atmospheric pressure (a "low") is at some place on the surface of the sea. The pressure at the center of the "low" is 64 mm-Hg less than the pressure at a large distance from the center. By how much will this cause the water level to rise at the...
7. ### Calculating the diameter of a bubble when it reaches the surface

Ok I got the right answer now. Thank you.
8. ### Calculating the diameter of a bubble when it reaches the surface

Homework Statement A scuba diver releases an air bubble of diameter 1.0 cm at a depth of 15 m below the surface of a lake. What will be the diameter of this bubble when it reaches the surface? Assume that the temperature of this bubble remains constant. Homework Equations p=F/A...
9. ### Finding diameter of a bubble when it reaches the surface.

Homework Statement A scuba diver releases an air bubble of diameter 1.0 cm at a depth of 15 m below the surface of a lake. What will be the diameter of this bubble when it reaches the surface? Assume that the temperature of the bubble remains constant. Homework Equations The...
10. ### Pressure problem

No there is not anything within the question other than what is stated above.
11. ### Pressure problem. Need help.

Homework Statement When a bicycle tire is filled early in the morning at 22 degrees C, the overpressure is 4.0 atm. What is the overpressure later in the day, when the temperature is 38 degrees C? Assume that the atmospheric pressure os 1.0 atm is constant. Homework Equations...
12. ### Pressure problem

I don't really know.
13. ### Pressure problem

Homework Statement Clouds of interstellar hydrogen gas have densities of up to 1.0 X 10^10 atoms/m^3 and temperatures of up to 1.0 X 10^4 K. What is the pressure in such a cloud? Homework Equations Ideal-Gas Law: pV=nRT The Attempt at a Solution I don't know how to find...