Molecular Physics | Thermodynamics Answers

Three thin walled infinitely long hollow cylinders of radii 5 cm, 10 cm and

15 cm are arranged concentrically as shown in Fig. 15.54. T1 = 1000 K and T3 = 300 K.

Assuming ε1 = ε2 = ε3 = 0.05 and vacuum in the spaces between the cylinders, calculate the

steady state temperature of cylinder surface 2 and heat flow per m2 area of cylinder 1

Two concentric spheres 210 mm and 300 mm diameters with the space between

them evacuated are to be used to store liquid air (– 153°C) in a room at 27°C. The surfaces of the

spheres are flushed with aluminium (ε = 0.03) and latent heat of vaporization of liquid air is

209.35 kJ/kg. Calculate the rate of evaporation of liquid air.

Liquid oxygen (boiling temperature = – 182°C) is to be stored in spherical

container of 30 cm diameter. The system is insulated by an evacuated space between inner sphere and

surrounding 45 cm inner diameter concentric sphere. For both spheres ε = 0.03 and temperature of the

outer sphere is 30°C. Estimate the rate of heat flow by radiation to the oxygen in the container

Pedro and Joanna decide to try a problem.

A baseball is thrown from the top of a tall building with an initial velocity of 10.5 m/s from a height of h = 10 m above the ground.

Find its speed when it reaches the ground if its launch angle is 37°.

v_f =___  m/s

Find its speed if it is launched horizontally.

v_f = ___ m/s

Under normal conditions, the human heart converts about 13.3 J of chemical energy per second into 1.33 W of mechanical power as it pumps blood throughout the body.

(a) Determine the number of Calories required to power the heart for one day, given that 1 Calorie equals 4186 J.

 __Cal

(b) Metabolizing 1 kg of fat can release about 9000 Calories of energy. What mass of metabolized fat (in kg) would power the heart for one day?

__kg

What average mechanical power (in W) must a 61.5 kg mountain climber generate to climb to the summit of a hill of height 345 m in 49.0 min? Note: Due to inefficiencies in converting chemical energy to mechanical energy, the amount calculated here is only a fraction of the power that must be produced by the climber's body.

__W

During an adiabatic process the pressure of the gas is found to be proportional to fourth power of temperature. The ideal gas would be A. H2

B. He C. CH2 d micture of H2 and He