Assume that a room at sea level was filled with a gas of oxygen molecules O2 in thermal equilibrium at 0 °C. There are 8 protons and 8 neutrons in the nucleus of an oxygen atom O. You may take the masses of the proton and the neutron to be the same, and ignore the mass of the electrons. 1 atm=1.01х105 N/m2 , ℏ=1.05х10-34 J·s , mp=1.67х10-27 kg.
a) What would the (particle) number density be according to the ideal gas law?
b) Compare the number density with the quantum concentration at the same temperature.
c) Is the gas in the classical or quantum regime?

The desk has a weight of 75 lb and a center of gravity at g. determine the initial acceleration of a desk when the man applies enough force f to overcome the static friction at a and b. also, find the vertical reactions on each of the two legs at a and at b. the coefficients of static and kinetic friction at a and b are ms = 0.5 and mk = 0.2, respectively

Mass (kg) force (n) 5 25 10 50 15 75 20 100 a student was trying to find the relationship between mass and force. he placed four different masses on a table and pulled them using a spring scale. the table shows the different masses used in the experiment and the force required to pull each mass. the student concluded that more force was required to pull heavier objects. what comment would you make regarding his conclusion? a) no clear relation can be observed between mass and force from the data. b) there is a direct proportion between the mass and force listed in the table. c) gravity should have been taken into account while performing the experiment. d) there is an inverse proportion between the mass and force listed in the table.

Aturntable a is built into a stage for use in a theatrical production. it is observed during a rehearsal that a trunk b starts to slide on the turntable 10 s after the turntable begins to rotate. knowing that the trunk undergoes a constant tangential acceleration of 0.31 m/s2, determine the coefficient of static friction between the trunk and the turntable.