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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°.
vf =___ m/s
Find its speed if it is launched horizontally.
vf = ___ 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
containers hold the same type of gas, but container B has twice the volume of container A. What is the average translational kinetic energy per molecule in container B? A. Twice that of container A
B. The same as that of container A C. Half that of container A
D. Impossible to determine
cube of its temperature. The ratio of Cp/Cv is A. 2
B. 44319 C. 44257
D. 44289
thermal capacity. Initial temperature of water is 80
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
A projectile of mass m is fired horizontally with an initial speed of v0 from a height of h above a flat, desert surface. Neglecting air friction, at the instant before the projectile hits the ground, find the following in terms of m, v0, h, and g.
(a) the work done by the force of gravity on the projectile
W =
(b) the change in kinetic energy of the projectile since it was fired
ΔKE =
(c) the final kinetic energy of the projectile
KEf =
