In a one-shell and eight-tube pass heat exchanger, the temperature of water flowing at rate of 50,000 lbm/h is raised from 70F to 150F. Hot air (c p = 0.25 Btu/lbmF) that flows on the tube side...
Ethylene glycol is heated from 25C to 40C at a rate of 2.5 kg/s in a horizontal copper tube (k = 386 W/mK) with an inner diameter of 2.0 cm and an outer diameter of 2.5 cm. A saturated vapor (T g =...
Oil is being cooled from 180°F to 120°F in a 1-shell and 2-tube heat exchanger with an overall heat transfer coefficient of 40 Btu/h·ft 2 ·°F. Water (c pc = 1.0...
Air (c p = 1005 J/kgK) enters a cross-flow heat exchanger at 20C at a rate of 3 kg/s, where it is heated by a hot water stream (c p = 4190 J/kgK) that enters the heat exchanger at 70C at a rate of 1...
Oil in an engine is being cooled by air in a crossflow heat exchanger, where both fluids are unmixed. Oil (c ph = 2047 J/kg·K) flowing with a flow rate of 0.026 kg/s enters the heat exchanger...
Consider a recuperative cross-flow heat exchanger (both fluids unmixed) used in a gas turbine system that carries the exhaust gases at a flow rate of 7.5 kg/s and a temperature of 500°C. The air...
Consider a water-to-water double-pipe heat exchanger whose flow arrangement is not known. The temperature measurements indicate that the cold water enters at 20C and leaves at 50C, while the hot...
Consider operation of a single pass cross-flow heat exchanger with water (c p = 4193 J/kgK) (mixed) and methanol (c p = 2577 J/kgK) (unmixed). Water entering and exiting the heat exchanger at 90C and...
Consider a cross-flow engine oil heater that uses ethylene glycol flowing at a temperature of 110°C to heat the oil initially at 10°C. The ethylene glycol enters a tube bank consisting of...
Saturated water vapor at 100°C condenses in a 1-shell and 2-tube heat exchanger with a surface area of 0.5 m 2 and an overall heat transfer coefficient of 2000 W/m 2 ·K. Cold water (c pc =...
By taking the limit as T 2 T 1 , show that when T 1 = T 2 for a heat exchanger, the T lm relation reduces to T lm = T 1 = T 2 .
A shell-and-tube heat exchanger with two-shell passes and 4-tube passes is used for cooling oil (c p = 2.0 kJ/kgK) from 125C to 55C. The coolant is water, which enters the shell side at 25C and...
Reconsider Prob. 22107. Using an appropriate software, investigate the effects of the condensing steam temperature and the tube diameter on the rate of heat transfer and the rate of condensation of...
Consider a closed loop heat exchanger that carries exit water (c p = 1 Btu/lbmF and = 62.4 lbm/ft 3 ) of a condenser side initially at 100F. The water flows through a 500 ft long stainless steel...
Consider the flow of saturated steam at 270.1 kPa that flows through the shell side of a shell-and-tube heat exchanger while the water flows through 4 tubes of diameter 1.25 cm at a rate of 0.25 kg/s...
A shell-and-tube heat exchanger with 1-shell pass and 14-tube passes is used to heat water in the tubes with geothermal steam condensing at 120°C (h fg = 2203 kJ/kg) on the shell side. The tubes...
A shell-and-tube heat exchanger is used for cooling 47 kg/s of a process stream flowing through the tubes from 160C to 100C. This heat exchanger has a total of 100 identical tubes, each with an...
A two-shell passes and four-tube passes heat exchanger is used for heating a hydrocarbon stream (c p = 2.0 kJ/kgK) steadily from 20C to 50C. A water stream enters the shellside at 80C and leaves at...
Saturated water vapor at 100°C condenses in the shell side of a one-shell and two-tube heat exchanger with a surface area of 0.5 m 2 and an overall heat transfer coefficient of 2000 W/m 2...
The condenser of a room air conditioner is designed to reject heat at a rate of 15,000 kJ/h from refrigerant-134a as the refrigerant is condensed at a temperature of 40°C. Air (c p = 1005...
Which of the following reactions are allowed and which are forbidden by the conservation laws appropriate to weak interactions? (a) + + e + e ; (b) K + + + e + e ; (c) K + 0 + + + ;...
Use the conservation of angular momentum and parity to determine possible angular momentum states in the reaction p + p + + and express the allowed transitions in spectroscopic notation for...
Which of the following processes are allowed in electromagnetic interactions and which are allowed in weak interactions via the exchange of a single W or Z 0 ? (a) K + 0 + e + + e , (b) K + + +...
Draw quark diagrams for the decays (a) D 0 K + + and (b) D 0 K + + . Estimate the ratio of their decay rates and compare this to the measured values.
Show that the momentum for a 2-kg brick parachuting straight downward at a constant speed of 8 m/s is 16 kg m/s. Impulse = Ft Momentum = mv
A race car rounds a curve at 60 m/s. The radius of the curve is 400 m, and the cars mass is 600 kg. (a) What is the cars (centripetal) acceleration? What is it in gs? (b) What is the centripetal...
A 0.1-kg ball is attached to a string and whirled around in a circle overhead. The string breaks if the force on it exceeds 60 N. What is the maximum speed the ball can have when the radius of the...
The energy emitted or absorbed in chemical processes is often quoted in kilo joules per mole (abbreviated mol) of reactants, where a mole contains N A 6.022 x 10 23 (Avogadros number) molecules (5)....
Design a transmission system to carry power from wind farms in North Dakota to the state of Illinois (about 1200 km). The system should handle Illinoiss summer time electricity demand of 42GW. Land...
A cylinder initially contains V 0 = 1 L of argon at temperature T 0 = 0 C and pressure p 0 = 1 atm. Suppose that the argon is somehow made to expand to a final volume V = 2 L in such a way that the...
Consider a building with 3200 ft 2 of walls. Assume the ceiling is well-insulated and compute the energy loss through the walls based on the following materials, assuming an indoor temperature of 70...
Show that the data in Table 9.6 satisfy the definitions of Gibbs and Helmholtz free energy, (1) ?G r =?H r ? T?S r and (2) ?H r = ?U r + p?V r . Quantity Value AUr Reaction internal energy +175.8...
Air conditioners are rated by their Energy Efficiency Ratio, or EER, defined as the cooling power P r (in Btu/h), divided by the total electric power input P e (in watts), measured with T + = 95 F...
Consider a throttled Otto cycle for an engine with the same parameters as Problem 11.1. In the throttled cycle assume that the spent fuelair mixture is ejected at 1 atm and brought in again at 0.5...
The first radioactive element discovered by Polish physicist Marie Curie was radium-226. It has a halflife of 1700 years. Suppose you obtained a microgram of pure 226 Ra. How long would you have to...
Check the quoted estimate of 4 10 9 tonnes of uranium from seawater quoted in this chapter. For how many years could this amount of uranium supply 100% of the worlds energy needs at the level of...
An approximate description of the Oklo uranium deposit is 90% uraninite (UO 2 ) by mass, saturated with water that acted as the moderator. Assume that the Oklo deposit was homogeneously saturated...
131 I is a dangerous fission product because iodine is preferentially absorbed by the thyroid gland in children. It has a half-life of about 8 days and emits a -particle with average energy 180 keV....
Consider a location for a solar energy installation in Arizona, at latitude 34 . Compute the declination on the following dates: (i) March 20 (spring equinox),(ii) April 20. Compute the length of...
Consider an idealized flat-plate solar collector with no conduction or convection losses, and with insolation 1000W/m 2 incident at an angle of 45 from the vertical. Assume that the collector is...
The thickness of the germanium (density 5.32 gm/c m 3 ) layer in a triple-junction PV is typically greater than 100 microns. If the overall cell efficiency is 40%, how many watts of PV capacity...
A large wind turbine blade is 50 m long and has a maximum chord length of 4 m at a point one-third of the way out from the wind turbine hub. When rotating at its design rate, the blade sees an air...
Make a very rough estimate of the thermal energy content of Earth, assuming that the core has radius 3480 km, temperature 4000 K, density 11000 kg/m 3 and heat capacity 800 J/K kg, and that the rest...
Consider the efficiency computed in the example single-flash cycle in Example 32.5. Use thermodynamic data on water to show that running the separator at T = 140 C or T = 160 C will decrease the...
Consider a house in a northern location that needs a total of 100 GJ of thermal energy over a winter season from November through March. Assume that the house has a ground source heat pump that...
Although doubly charged baryons have been found (baryons with net charge 12), no doubly charged mesons have yet been identified. What effect on the quark model would there be if a meson of charge 12...
If you scuff electrons from your shoes while walking across a silk rug, are you negatively or positively charged?
Two bunnies hop at slightly different rates but remain side by side. The first takes 50 hops per minute and the other takes 48 hops per minute. If they begin hopping together, when will they again be...
Would you use a physical model or a conceptual model to describe the following: a gold coin, a dollar bill, a car engine, air pollution, a virus, the spread of sexually transmitted disease?
Suppose that a pancake recipe designed to feed three people calls for 600 mL of flour. How many milliliters of flour would you use if you wanted to extend the recipe to feed five people?
The centripetal acceleration depends upon the square of the speed rather than just being proportional to the speed. Why does the speed enter twice? Explain.
Estimate how many solar panels or wind turbines are needed to produce the same amount of electrical energy as the 10 kt of coal that can be extracted in a long wall mining operation in one year by...
Compute the fraction of Carnot efficiency realized by a coal plant operating at 600 C and 45% efficiency (assume ambient temperature of 300 K). If another plant operates at the same fraction of...
Compute and compare the amount of carbon released per GJ of delivered energy by (a) a coal plant operating at 35% efficiency, (b) a natural gas combined cycle plant operating at 60% efficiency, (c)...
Assume that 1% of a net radiative forcing of 3.7 W/m 2 world wide goes to melting ice over land. Estimate the rate of sea level rise from this melting.
Assume that the rate of carbon emission at 10 Gt/year increases at a constant rate to a maximum of 20 Gt/year in 2050, and then decreases at the same rate. Assume that ocean and land biomass together...
Thomas Edisons first DC power plant on Pearl St.in New York City produced roughly 100 kW at 110 V(DC), which was distributed over two copper wires spanning distances of order 1 km. Suppose resistive...
A homeowner is trying to decide whether to heat with a furnace rated at 95% efficiency or by an electrically powered heat pump. She lives in a town where electricity is produced by a coal-fired power...
A force of 40 N pushes down on the movable piston of a closed cylinder containing a gas. The pistons area is 0.5 m 2 . What pressure does this produce in the gas?
If 200 cal of heat are added to a system, how much energy has been added in joules?
If 600 J of heat are added to 50 g of water initially at 20C, a. how much energy is this in calories? b. what is the final temperature of the water?
Is it possible to produce a longitudinal wave on a rope? Explain.
When two waves on separate ropes reach the spliced junction out of phase with one another, they interfere destructively producing no wave beyond the splice. What happens then to the energy carried by...
What is the beat frequency that results when an 880-Hz note is played with a 660-Hz note? If this beat frequency is heard as a musical tone, how is this tone related to the original two notes? What...
A fish lies 80 cm below the surface of a clear pond. If the index of refraction of water is assumed to be 1.33 and that of air is approximately 1, how far below the surface does the fish appear to a...
A rock appears to lie just 24 cm below the surface of a smooth stream when viewed from above the surface of the stream. Using the indices of refraction given in exercise 2, what is the actual...
A positive lens has a focal length of 6 cm. An object is located 24 cm from the lens. a. How far from the lens is the image? b. Is the image real or virtual, erect or inverted? c. Trace three rays...
A positive lens has a focal length of 12 cm. An object is located at a distance of 3 cm from the lens. a. How far from the lens is the image? b. Is the image real or virtual, erect or inverted? c....
A negative lens has a focal length of -10 cm. An object is located 20 cm from the lens. a. How far from the lens is the image? b. Is the image real or virtual, erect or inverted?
An object is located at the focal point of a positive lens with a focal length of 12 cm. a. What is the image distance predicted by the object image distance formula? b. Trace two rays to confirm the...
How many more electrons can fit within the valence shell of a fluorine atom?
Some bottled water is now advertised as containing extra quantities of Vitamin O, which is a marketing gimmick for selling oxygen, O 2 . Might this bottled water actually contain extra quantities of...
For every question we can answer with our space telescopes, there are more questions that arise. Why, then, should we continue looking for answers?
Describe the connection between special and general relativity
Compare and contrast the Big Bang and a black hole?
If we cant even predict the weather, how can we ever expect to predict the fate of the universe?
If there are so many stars and galaxies, why do we see so much darkness in the clear night sky?
Mass can transform into energy, and energy can transform into mass, in accordance with Einsteins equation E = mc 2 . If the amount of massenergy in the universe remains constant, what happens to the...
If the universe were unchanging and there were an infinite number of stars, what effect might this have on the darkness of a clear night sky?
Why is dark energy not called the dark force?
What is one important difference between dark matter and dark energy?
Is space just the absence of matter?
What is the relationship between dark energy and Einsteins cosmological constant?
If dark matter is affected by gravity, might there be lots of it surrounding us here on the surface of Earth?
The y-axis in the largest graph of Figure 28.27 is given in units of redshift, z. How is this related to velocity, as given in the y-axis of the smaller graph above it? Original Hubble data 50 100...
Why doesnt dark matter clump together as effectively as ordinary matter?
What force allows dark matter to clump?
Early astronomers such as Kepler and Newton developed the laws of gravity on the basis of the motion of the planets around the Sun. How might these laws be different if our solar system were set...
What might we assume about the distribution of dark matter if the planets in our solar system all orbited the Sun at about the same speed?
If we are made of stardust, what are stars made of?
How do the distances in Exercise 73 compare as seen in the frame of reference of an observer on a stationary planet (Figure 28.19)?
Inside the moving compartment of Figure 28.18, light travels a certain distance to the front end and a certain distance to the back end of the compartment. How do these distances compare as seen in...
Astronomers view light coming from distant galaxies that are receding from us at very high speeds, greater than 10% of the speed of light (that is, at about 30,000 km/s). How fast does this light...
Assume the onboard light in Figure 28.18 is fixed to the front wall. For whom does this light hit the back wall first: the onboard observer or the observer at rest on a planet as shown in Figure...
When do clocks move slowest on Mercury?
A man leaves his identical twin brother behind to live on another planet that is half as massive. After living apart for many years, the two brothers are reunited on the original planet. According to...
Being ultra-sensitive, should a person who wants to live a long life live at the top or at the bottom of a tall apartment building?
Several billion years in the future, our Sun will grow in size to become a red giant, whose surface will extend to the present orbit of Earth. After this happens, will the slowing of time on the Suns...
Where does a clock run slower: at the front end or the back end of an accelerating spaceship?
Assume the onboard light in Figure 28.18 is fixed to the back wall. For whom does this light hit the front wall first: the onboard observer or the observer at rest on a planet as shown in Figure...