Molecular Physics | Thermodynamics Answers

A group of 50 persons attended a secret meeting in a room 12m x 10m x 3m high. The

room is completely sealed off and insulated. Each person gives off 150 kcal/hr of heat

and occupies a volume of 0.2 cubic meters. The room has an initial pressure of 101.3

kpa and 16C. calculate the room temp after 10minutes.

A vessel of 58L capacity is well insulated and is divided equally by a rigid conducting

diaphragm. Initially both halves contain air at pressure of 137.8 Kpa and 413.4 Kpa

and temperature of 27C and 177C respectively. Find the increase of entropy of the

system

a) Find change in wavelength of 80-ppm x-rays that are scattered 120 degree by a target.

b)Find the angle between the directions of recoil electron and incident photon.

c) Find the energy of recoil electron.

A person weighs 837.72 newtons when she is on earth but only weigh 474.01 newtons when she is at the surface of another planet. What is the acceleration due to gravity on the planet?

Dry hydrogen is trapped by a pellet of mercury in a uniform capillary tube closed at one end. If the length of the

column of hydrogen at 270oC is 1.0m, at what temperature will the length be 1.20m?

The uniform bar weighs 45 N and is subjected to the forces as shown. Find the magnitude, location and direction of the force needed to keep the bar in equilibrium

Example:

A steel railroad track has a length of 30.000 m when the temperature is 0°C. What is its length on

a hot day when the temperature is 40.0°C? (b) Suppose the track is nailed down so that it

can’t expand. What stress results in the track due to the temperature change

A 200g of gas was heated from 50°C to around 120°C. The gas expanded in a piston-cylinder apparatus from 2.0L of initial volume to find a volume of 10.0L against an external pressure of 3.0 atm. Calculate for the change in the internal energy. The specific heat of water is 2.19 J/g×°C)

Considering the encircle part of the pumping system as shown below. Assuming a fresh water flowing in the discharge pipe with a velocity of 5 m/s.

Dynamic viscosity of oil used for lubrication between a shaft and a sleeve is 0.8Ns/m². The shaft is of d=0.5m and rotates at 190rpm. Calculate the horsepower lost in bearing for a sleeve length of 0.1m. Thickness of oil film is 2mm