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...
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...
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...
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}}...
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
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...
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...
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...
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...
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...