Tuesday
May 21, 2013

# Search: Physics (Heat Engines)

Number of results: 102,001

Physics
Which of these types of motors or engines are heat engines? a. an automobile engine b. an electric motor c. a steam turbine
Sunday, January 2, 2011 at 10:46pm by Anonymous

Physics
Which of these types of motors or engines are heat engines? a. an automobile engine b. an electric motor c. a steam turbine
Tuesday, December 28, 2010 at 12:33pm by Sylvia

Physics (Heat Engines)
In a maximum-efficiency "Carnot" cycle, the ratio Qout/Qin = Tout/Tin because the entropy change when heat is absorbed and released by the fluid is the same. T remains the same during each process. Therefore e = 1 - Tout/Tin = 3/7, and Wout = 3/7 * 2800 = 1200 J ...
Saturday, March 6, 2010 at 10:32pm by drwls

Physics
Heat engines produce mechanical or electrical energy from heat. That excludes electric motors from consideration. A steam turbine can in some cases be one PART of a heat engine, but a burner, geothermal source or nuclear reactor would have to be part of the complete heat ...
Sunday, January 2, 2011 at 10:46pm by drwls

AP Physics B (Heat Engines)
18. (II) At a steam power plant, steam engines work in pairs, the heat output of the first one being the approximate ehat input of the second. Th eoperating temeprautres of the first are 680 degrees C and 430 degrees C, and of the second 415 degrees C and 280 degrees C. If the...
Wednesday, December 16, 2009 at 8:12pm by Joe

Physics (Heat Engines)
wait no the answer is A how though?
Saturday, March 6, 2010 at 10:32pm by Kate

SCIENCE
A steady-state heat engine that absorbs 8000 J from a high-temperature reservoir and rejects 1000 J to a cold heat sink would produce 7000 J of work. There would be no other place for the energy to go. The heat engine efficiency would be 87.5%. I know of no heat engines that ...
Thursday, August 18, 2011 at 12:36am by drwls

AP Physics B (Heat Engines)
Do not multiply the percentages you calculated by .65, because you already multiplied it to get 17% and 14.6% :)
Wednesday, December 16, 2009 at 8:12pm by T

Physics
First get the maximum possible efficiency from the Carnot cycle formula (Wout)/(Qin) max = 1 - (Tin/Tout) = 1 - (350/650) = 46.2% That efficiency applies to the work out per cycle or the average power divided by the heat transfer rate in. You want power out, so compute the ...
Sunday, July 18, 2010 at 8:45am by drwls

Physics
18. (II) At a steam power plant, steam engines work in pairs, the heat output of the first one being the approximate ehat input of the second. Th eoperating temeprautres of the first are 680 degrees C and 430 degrees C, and of the second 415 degrees C and 280 degrees C. If the...
Wednesday, December 16, 2009 at 10:11pm by Kate

Physics (Heat Engines)
21. A heat engine operates in a cycle between temperatures 700 K and 400 K. The heat input to the engine during each cycle is 2800 J. What is the maximum possible work done by the engine in each cycle? (A) 1200 J (B) 1600 J (C) 2100 J (D) 2800 J (E) 4400 J I believe that the ...
Saturday, March 6, 2010 at 10:32pm by Kate

physics
b. Bob Pursley's equation only applies for Carnot cycle engines. Real engines are not built that way. Stirling cycle engine are supposed to come close. In your case, you should use the actual work out and heat out data. Wout (per cycle) = Qin - Qout = 490 J Efficiency = ...
Sunday, January 1, 2012 at 9:39am by drwls

physics(mechanics)
how does the engines get cooled when the vehicle moves in a hill ramp.?i ask this question because its said that cooling fans are drived by the rotation of the engines sothat the cooling fans are mounted in the engine casing.If thats is the case then at ramps engine run slowly...
Saturday, May 11, 2013 at 11:14pm by NANDHU

physics
In December of 1989, a KLM Boeing 747 airplane carrying 231 passengers entered a cloud of ejecta from an Alaskan volcanic eruption. All four engines went out, and the plane fell from 27800 ft to 13700 ft before the engines could be restarted. It then landed safely. how long ...
Thursday, January 19, 2012 at 2:13pm by Amy

physics
What is being done to reduce emissions from gasoline engines in automobiles? What more can be done in the future? Do you think gasoline engines will become a thing of the past?
Thursday, September 23, 2010 at 12:39pm by Anonymous

chemistry
how do reciprocating heat engines work?
Thursday, February 11, 2010 at 3:26am by alex

AP Physics B (Heat Engines)
the work that engine one does is (using your numbers) .65*.17Heatinput Then the waste heat is Heatinput- work doneinengine1 But this is used as input to engine2, so the work done in engine 2 is Heatinput*massrate(1-.65*.17)(.65*.14) But the total work done is Heat input*...
Wednesday, December 16, 2009 at 8:12pm by bobpursley

physics
The hot reservoir for a Carnot engine has a temperature of 926 K, while the cold reservoir has a temperature of 441 K. The heat input for this engine is 3730 J. The 441-K reservoir also serves as the hot reservoir for a second Carnot engine. This second engine uses the ...
Saturday, December 1, 2012 at 6:53pm by angie

PHYSICS
In December of 1989, a KLM Boeing 747 airplane carrying 231 passengers entered a cloud of ejecta from an Alaskan volcanic eruption. All four engines went out, and the plane fell from 27800 ft to 13700 ft before the engines could be restarted. It then landed safely in Anchorage...
Thursday, January 19, 2012 at 12:58pm by Amy

Physics
In December of 1989, a KLM Boeing 747 airplane carrying 231 passengers entered a cloud of ejecta from an Alaskan volcanic eruption. All four engines went out, and the plane fell from 27800 ft to 13700 ft before the engines could be restarted. It then landed safely in Anchorage...
Tuesday, January 17, 2012 at 6:12pm by Amy

Math
Hiroshi has 4 engines and 18 box cars. Find the ratio of engines to box cars. Write the ratio as a fraction in simplest form. Then explain its meaning. 2/9? 2 engines to 9 box cars? Am I explaining what their meanings are correctly?
Friday, November 16, 2012 at 9:38pm by Jerald

AP Physics B (Heat Engines)
I know that efficiency is e = |W|/|QH| were the H is the subscript I know that 900 MW is a value of power which is not work I know that |QH| is 2.8 E8 J/kg but I do not like the units for this, J/kg, as I thought Q was measured in joules only... How do I find the work done?
Wednesday, December 16, 2009 at 8:12pm by Joe

physics
I will be happy to critique your thinking. Add the following heats: heat to melt ice heat to warm water to 100C heat to change water to steam heat to heat steam to 150C
Thursday, April 21, 2011 at 12:39am by bobpursley

Physics
Heat lost by spoon = heat gained by water Use that heat, the aluminum temperature drop, and the specific heat of aluminum to get the mass. Ignore the styrafoam mass. It acts as an insulator to keep the heat inside, and weighs very little.
Saturday, May 7, 2011 at 12:56am by drwls

chemistry
Ethanol's boiling point is too low for use in automobile engines. Ethylene glycol doesn't have the specific heat capacity that water has.
Tuesday, February 8, 2011 at 9:37am by DrBob222

Physics
sorry to repost (again) but I'm not understanding how to solve this: A rocket is launched at an angle of 42&#9702; above the horizontal with an initial speed of 76 m/s. It moves for 9 s along its initial line of motion with an acceleration of 29 m/s^2. At this time its...
Monday, September 6, 2010 at 11:48pm by John

Physics
sorry to repost (again) but I'm not understanding how to solve this: A rocket is launched at an angle of 42&#9702; above the horizontal with an initial speed of 76 m/s. It moves for 9 s along its initial line of motion with an acceleration of 29 m/s^2. At this time its...
Monday, September 6, 2010 at 11:40pm by John

Physics
A fighter jet is launched from an aircraft carrier with the aid of its own engines and a steam-powered catapult. The thrust of its engines is 2.1 105 N. In being launched from rest it moves through a distance of 87 m and has a kinetic energy of 3.8 107 J at lift-off. What is ...
Saturday, November 13, 2010 at 8:46am by Patty

Math
3/8 * 40 = 120/8 = 15 If you post your answers to these questions, we'll be glad to check them. How many engines were in each part? How many parts could climb the hill? How many engines could climb the hill? How many parts could not climb the hill? How many engines could ...
Tuesday, March 23, 2010 at 5:00pm by Ms. Sue

Physics
There may be friction in a hydraulic jack, and a bit of heat produced, but that does not make it a heat engine. A heat engine converts heat to mechanical energy. None of the things on your list do that.
Sunday, January 2, 2011 at 11:38pm by drwls

Physics
figure this in three parts: heat to heat water from 25C to 100C heat to vaporize water at 100C heat to heat steam from 100C to 120C add them
Thursday, November 18, 2010 at 8:46pm by bobpursley

Physics
A fighter jet is launched from an aircraft carrier with the aid of its own engines and a steam-powered catapult. The thrust of its engines is 3.82 x 105 N. In being launched from rest it moves through a distance of 57.2 m and has a kinetic energy of 5.71 x 107 J at lift-off. ...
Friday, December 14, 2012 at 9:43pm by Ricardo

Physics
A fighter jet is launched from an aircraft carrier with the aid of its own engines and a steam-powered catapult. The thrust of its engines is 2.10 105 N. In being launched from rest it moves through a distance of 87 m and has a kinetic energy of 4.30 107 J at lift-off. What is...
Sunday, November 11, 2012 at 6:35am by Donald

Physics
all HELP appreciated! Thank You! A fighter jet is launched from an aircraft carrier with the aid of its own engines and a steam-powered catapult. The thrust of its engines is 2.1 105 N. In being launched from rest it moves through a distance of 87 m and has a kinetic energy of...
Monday, October 19, 2009 at 7:29pm by Pablo

Physics
A space probe has two engines. Each generates the same amount of force when fired, and the directions of these forces can be independently adjusted. When the engines are fired simultaneously and each applies its force in the same direction, the probe, starting from rest, takes...
Wednesday, February 13, 2013 at 7:59pm by Randy

Physics
A space probe has two engines. Each generates the same amount of force when fired, and the directions of these forces can be independently adjusted. When the engines are fired simultaneously and each applies its force in the same direction, the probe, starting from rest, takes...
Monday, September 17, 2007 at 11:52pm by James

Physics
How much heat is added to a 10.0 g of ice at -20.0 degrees Celsius to convert it to steam at 120.0 degrees Celsius? compute and add the following heats: heat to heat ice from -20C to 0C heat to melt ice at 0C Heat to heat water from 0 to 100C heat to convert water to steam at ...
Monday, March 5, 2007 at 7:45pm by Marie

physics
A space probe has two engines. Each generates the same amount of force when fired, and the directions of these forces can be independently adjusted. When the engines are fired simultaneously and each applies its force in the same direction, the probe, starting from rest, takes...
Tuesday, October 12, 2010 at 3:50pm by deanna

Math
3/8 of the 40 little engines could climb the hill. How many engines were in each part? How many parts could climb the hill? How many engines could climb the hill? How many parts could not climb the hill? How many engines could not climb the hill?
Tuesday, March 23, 2010 at 5:00pm by Malory

Physics
1. On a spacecraft, two engines are turned on for 648 s at a moment when the velocity of the craft has x and y components of v0x = 4360 m/s and v0y = 6270 m/s. While the engines are &#64257;ring the craft undergoes a displacement that has components of x = 4.11 × 106...
Monday, October 1, 2012 at 11:28pm by Thomas

physics
A fighter jet is launched from an aircraft carrier with the aid of its own engines and a steam-powered catapult. The thrust of its engines is 2.4 x 10^5 N. In being launched from rest it moves through a distance of 87 m and has a kinetic energy of 5.0 x 10^7 J at lift-off. ...
Wednesday, October 15, 2008 at 9:25pm by nj

physics
The efficiency of the first Carnot engine is 1 - (441/926) = 0.5238 The work out of that engine is 3730*0.5238 = 1954 J The heat output of that engine is 3730-1954 = 1776 J. That heat is the input to the second engine. The second engine's efficiency is 1 - (191/441) = 0....
Saturday, December 1, 2012 at 6:53pm by drwls

Physics
heat in = mass * heat capacity * change in temp 3.5*10^4 = 2.3* heat capacity*(T-39) I am not about to look up the heat capacity of iron in Joules/kgdegK. It is in your book
Wednesday, June 20, 2012 at 3:10pm by Damon

physics
Any gas will absorb heat if you heat it up. The added heat makes the molecules move faster.
Tuesday, February 23, 2010 at 1:21am by drwls

Physics
Find the heat necessary to change 2.5kg of water (ice) at -2 degrees C to steam at 105 degrees C. specific heat ice= 2060 specific heat water= 4180 specific heat steam= 2020 heat of fusion= 3.34X10^5 heat of vaporization= 2.26X10^6
Thursday, November 18, 2010 at 8:49pm by Brittany

univ. physics
A heat pump has a coefficient of performance of 4.5. If the heat pump absorbs 46.1 cal of heat from the cold outdoors in each cycle, what is the amount of heat expelled to the warm indoors? (in cal)
Thursday, December 13, 2012 at 5:21pm by kate

physics
Heat to do what? expand it a certain length? heat it to a certain temperature? If you are just looking at heat content for a specific temperature change, heat is directly proportional to mass, which is directly related to volume. heat then equals 1/4 of the original. But I ...
Tuesday, July 3, 2012 at 7:19am by bobpursley

physics
A heat pump has a coefficient of performance of 4.5. If the heat pump absorbs 46.1 cal of heat from the cold outdoors in each cycle, what is the amount of heat expelled to the warm indoors? (in cal) tried everything but got nothing.
Monday, December 17, 2012 at 12:00pm by jimmy

add the following energyies: heat to heat ice at -10 to 0 heat to melt 20 g ice at 0C Heat to heat water from 0C to 100C heat to vaporize 20gwater at 100C. heat to heat steam from 100C to 200C
Tuesday, January 5, 2010 at 6:46pm by bobpursley

Physics
The potential energy becomes heat, Q. Use the heat to compute the temperature rise. Delta T = Q/(M*C) = (1/2)M g H/(M*C) = (1/2)g H/C C is the water specific heat, 4180 joules/kg C
Tuesday, June 28, 2011 at 12:39am by drwls

Physics
a. heat= 200g*1cal/gC * 60C b. heat=power*time time= heat/power= above heat/power. Well, at this point, you have to change calories to joules, as 50watts=50joules/sec
Friday, July 2, 2010 at 6:19pm by bobpursley

Physics
The heat of fusion is 80 cal/g = 335 J/g The specific heat of ice 2.11 J/g*degC To heat the ice to 0 C requires 2000 g * 8 C *2.11 J/c*C = 33,760 J There is more than enough heat to melt all of the ice.
Tuesday, May 10, 2011 at 8:20pm by drwls

Probabilities
Company has 90 cars in stock with 4 cylinder engines and 290 with 6 cylinder engines. There are no other cars in stock. 130 of these cars, including 20 of those with 4 cylinder engines have air conditioning. One car on the lot is selected at random. The probability that this ...
Tuesday, April 21, 2009 at 2:05pm by Andrey L

Statistics
A company has two factories in which they manufacture engines. Once a month they randomly select 10 engines from each factory and test if there is a difference in performance in engines made in the two factories. This month the average output of the motors from Factory 1 is ...
Monday, June 18, 2012 at 10:55pm by Mike

Science/Physics
The nerves in our skin do not sense temperature, they sense heat flow. If heat flow is great, we sense it as hot. If heat flow is outward, we sense it as cold. The seat has stored little heat, so touching it wont get much heat flow. The windshield actually has stored more heat...
Friday, December 9, 2011 at 6:18pm by bobpursley

Physics
Acceleration is not increasing with engines on. It is constant. When the engines are on, Y = 76 sin42 t + (1/2)(29 sin 42)t^2 X = 76 cos42 t + (1/2)(29 cos 42)t^2 Use t = 9 s to find out the location and speed at burnoout. Then write a new equation for the position after that...
Monday, September 6, 2010 at 11:48pm by drwls

PHYSICS'S
you have three parts: a. Heat the water to 100C b. vaporize the water at 100C c. heat the steam to 110C a. heat=m*cwater*(100-20) b. heat=m*Hv c. heat=m*csteam*(110-100) cwater is specific heat capacity of water Hv is the heat of vaporization of water. Csteam is specific heat ...
Sunday, March 31, 2013 at 6:28pm by bobpursley

physics
A 1560 rocket is to be launched with an initial upward speed of 53.0 . In order to assist its engines, the engineers will start it from rest on a ramp that rises 53 above the horizontal (the figure ). At the bottom, the ramp turns upward and launches the rocket vertically. The...
Wednesday, December 14, 2011 at 9:38am by Anonymous

physics
heat lost by ice=MLf =22*3.34*10^5 J =7348000 J since heat gained =heat lost 7348000 joules of heat energy is absorbed by the ice box.
Saturday, November 20, 2010 at 10:06am by sanjeet

Science
Organisms that maintain a constant body temperature rely on the heat produced by cells. Where does this heat come from? A) Special metabolic pathways exist just for the production of heat. B) Mitochondria produce heat in the form of ATP. C) Plants store up heat as they perform...
Wednesday, October 26, 2011 at 8:59pm by Jason

Physics
Heat is transferred from the two added blocks to the water and calorimeter. You can calculate that amount of heat from the increase in temperature. Set it equal to the heat lost by the two added blocks, and solve for the unknown specific heat of the second sample.
Tuesday, November 30, 2010 at 8:44am by drwls

physics
They need to tell you: (1) if water is flowing through, and at what rate (2) convective heat loss to the air. (3) radiative heat loss They probably expect you to assume no flow and neglect the loss terms. This will lead to a high prediction of the temperature rise. This is a ...
Saturday, March 3, 2012 at 11:18pm by drwls

college physics
Please show some effort of your own other than changing a letter in your name each time you post. (1) Look up the specific heats of glass, aluminum and water. (2) Compute the amount of heat energy gained by those three materials as they heat from 12.5 to 35 C. Call that heat Q...
Thursday, May 6, 2010 at 12:38am by drwls

Physics
what is the relationship between specific heat capacity and conduction? if an substance has a higher heat capacity is it a better heat conductor?
Thursday, March 26, 2009 at 10:41pm by Chris

Physics
specific heat capactiy is the heatcapacity of a substance PER mass Heat capacity is the heat absorbed per degree temperature.
Saturday, April 5, 2008 at 4:54pm by bobpursley

operations managment
Harley-Davidson has its engine assembly plant in Milwaukee and its motorcycle assembly plant in Pennsylvania. Engines are transported between the two plants using trucks, with each trip costing \$1,000. The motorcycle plant assembles and sells 300 motorcycles each day. Each ...
Tuesday, November 24, 2009 at 9:11am by Jasmine

Chemistry
heat lost by hot water + heat gained by cold water = 0 heat lostt or heat gain is mass x specific heat x (Tfinal-Tinitial)
Tuesday, June 7, 2011 at 8:23am by DrBob222

physics
find the heat needed... Heatneeded=masswater*c(0-23)-masswater*Lf+massAl*Cal*(0-23) Notice this heat is "negative), meaning it was lost. (it is negative heat gained). now, the heat the ice gained. massice*Cice*(0-Ti) Now add the heats gained...set to zero. heat ice gained...
Tuesday, June 29, 2010 at 8:53pm by bobpursley

physics
Look up the heat of fusion of ethanol. Heat in water freezing= masswater*Hfwater Heat in alchol freezing=massalcohol*Hfalc set the equal, and solve for mass of alcohol.
Sunday, February 10, 2008 at 5:46pm by bobpursley

Physics
The steam gives out more heat in cooling to body temperature because it has to give off the heat of the phase change from steam to water (heat of vaporization) as well as the heat required for the temperature change from 100 C to body temp.
Sunday, February 20, 2011 at 5:20pm by Damon

Help me! Physics
Heat gained by aluminum equals heat lost by copper. Let T be the final equilibrium temperature of both. The heat gain of each metal is Q = M*C*(T2 - T1). It heat is lost, that number is negative 2.6*0.22*(T-13) = 10.2*0.093*(93-T) Solve for T. 0.572T - 7.436 = 88.22 - 0.9486 T...
Thursday, January 17, 2013 at 7:10pm by drwls

physics 2 **
The heat lost by the horseshoe equals the heat gained by th water. Write an equation that says this and solve it for the final temperature. They should have told you what the horseshoe is made of, because you will need to know its specific heat.
Thursday, December 4, 2008 at 11:55pm by drwls

Physics
"The energy that is transferred as heat to or from the object with the larger heat capacity must be greater than the energy that is transferred as heat to or from the object with the smaller heat capacity." Can someone explain why this concept is true or false?
Tuesday, June 21, 2011 at 9:49pm by Josh

PHYSICS!!
final temp t Cv = specific heat capacity of fluid heat in to lower = 478 * Cv * (t-34) heat out of upper = 618 *Cv*(73-t) heat into cold = heat out of hot 478 (t-34) = 618 (73-t) solve for t
Sunday, April 11, 2010 at 4:35pm by Damon

Physics
you need to first look for the latent heat of fusion (Lf) --- this is a constant, then use the formula: Q = m(Lf) where Q = heat in Joules, m = mass in grams *since it melted, it definitely absorbed/gained heat, thus Q is (+) so there,, :)
Thursday, October 28, 2010 at 8:54am by jai

Physics
You balance the heat equation. heat gained by melting ice+heat gained by remaining ice warming up + heat gained by hot water=0 This of course means that the nonmelted ice is at a final temperature of zero, otherwise there cannot be an ice/water mxture. Heat gained by melting ...
Thursday, July 19, 2012 at 4:46pm by bobpursley

physics
Calculate the number of Joules of heat required (Q), using the mass, specific heat of ice, temperature rise and latent heat of fusion. Q = M[10 C(ice) + Latent heat] = 1.00[10*2090 + 3.33*10^5] = 3.54*10^5 J Then divide that by the heating rate in Watts (J/s) for the answer in...
Tuesday, May 4, 2010 at 9:12pm by drwls

Physics
I have no idea what a halogen cooktop might be. I suspect it radiates to heat. (halogen bulbs radiate heat, infrared, as well as light) However if you want something to absorb radiation and heat up, make it black, not a reflector.
Saturday, December 1, 2012 at 10:49pm by Damon

Physics
92% of the 355 W becomes body heat. That equals 327 W. In one hour, that is a total heat energy of 3600*327 = 1.18*10^6 J. Divide that by the latent heat of vaporization for the # of kg of sweat evaporated
Saturday, May 1, 2010 at 12:21am by drwls

physics
Heat loss from M grams steam cooling and condensing to 50 C liquid = heat gained by 250 g water increasing from 22 to 50 C PLUS heat gained by beacker. Write that as an equation and solve for M. You will need to know the specific heat of steam in the gas phase (about 0.4 cal/g...
Thursday, January 20, 2011 at 4:54pm by drwls

physics
This is two problems rolled into one. q1 = heat required to raise T of solid from 40.0 C to 90.0 C. q1 = mass x specific heat x delta T. q2 = heat required to melt the solid once the T has reached 90.0 C. q2 = mass x heat of fusion. Total heat = q1 + q2.
Thursday, April 3, 2008 at 5:14pm by DrBob222

physics
Call final temp = T Heat lost by Al = specific heat AL * mass of Al * (80-T) Heat gained by water - specific heat of H2O * mass of H2O *(T-20) Then Heat lost by Al = Heat gained by H2O
Sunday, July 4, 2010 at 8:57am by Damon

Physics
A model rocket is launched straight upward with an initial speed of 58.0 m/s. It accelerates with a constant upward acceleration of 1.50 m/s2 until its engines stop at an altitude of 120 m. (a) What can you say about the motion of the rocket after its engines stop? (b) What is...
Tuesday, February 7, 2012 at 6:56pm by Haroula

physics
Compressing gases requires work and the resulting energy is usually converted to heat; if this heat does not escape, the gas's temperature will rise. This effect is used in diesel engines: The compressed air gets so hot that when the fuel is injected, it ignites without ...
Monday, November 8, 2010 at 12:47pm by Ashleigh

physics
The sum of the heats gained is zero. heat added to heat copper+ heat added to water + heat added to alumium cup=0 245*Ccopper*(Tf-285C)+825*Cwater*(Tf-12)+145*Caluminum*(Tf-12)=0 solve for Tf
Friday, April 22, 2011 at 3:46pm by bobpursley

physics
Power*time= Heat= Mass*Hvwater + Mass*(100-21)*specific heat of water. Watch specific heat, heat of vaporization units, make certain they match your mass units. Solve for time.
Sunday, January 20, 2008 at 9:07pm by bobpursley

physics
The maximum possible efficiency of a heat engine which exhaust its heat at a temperature of 46.0o is 39.0 percent. What is the minimum value of the temperature at which the engine takes in heat? (in oC).
Sunday, November 18, 2012 at 1:37pm by chelsea

physics
The maximum possible efficiency of a heat engine which exhaust its heat at a temperature of 46.0o is 39.0 percent. What is the minimum value of the temperature at which the engine takes in heat? (in oC).
Friday, November 16, 2012 at 9:17pm by Erika

Physics
The amount of heat transfered to the water is 150*7.1*1.0 = 1065 calories. Removing that amount of heat from 100 g of the substance caused its temperature to drop 67.9 C. The specific heat can be calculated from that information. C = Q/(M*deltaT) = 0.157 Cal/gm C = 0.657 J/g K
Sunday, March 21, 2010 at 10:04pm by drwls

Chemistry
Heat energy is the amount of heat used or available; heat capacity is the ability of a substance to absorb heat. Heat energy is measured in J or kJ and heat capacity is measured in J/g*K.
Saturday, April 21, 2012 at 3:15pm by DrBob222

Physics
The dark sunglasses will absorb the heat, and less of the heat resonates back out, so my answer would be the dark glasses. The heat is just reflected back or passed through, not absorbed.
Thursday, February 14, 2008 at 6:47pm by Emily

Check 1 question.
Yes, you are correct. The first one is heat fusion. The second is heat of combustion. The third is heat of decomposition. The fourth is heat of solution.
Friday, June 22, 2012 at 1:39pm by DrBob222

Physics
Compute the energy deposited in the body as heat in that time interval, and divide it by the heat capacity of the body. The heat deposited is (0.82)(501 W)(3600 s) = __ Joules The heat capacity is (71.0 kg)(3480 J/kg C)= __ J/C
Friday, November 21, 2008 at 12:29am by drwls

Physics
The heat generated by the students at the end of one hour is 10*(200 J/s)*3600 s = ___ Joules Divide that by the heat capacity of the air in the room, (Volume)*(air density)*Specific heat) The ratio will be the temperature rise. The high value is the result of erroneous ...
Tuesday, November 30, 2010 at 11:05am by drwls

Physics
(a) Calculate the rate of heat transfer to the substance using P = V^2/R. Multiply by 240 seonds for the number of Joules. That energy divided by the mass and 60 C is the specific heat (b) time required = (Mass)(Heat of fusion)/(Power) We will be happy to check your work
Sunday, May 10, 2009 at 5:46pm by drwls

Active physics
I think you mean heat, not hear. Add the heat required for the following steps: (1) heat ice from -25C to 0 C (2) melt the ice (3) heat water from 0 C to 100 C (4) vaporize the water to steam (5) heat the steam from 110 C to 119 C. (Assume constant pressure) You will need the ...
Monday, May 9, 2011 at 9:00am by drwls

Physics
Nuts to your I know paragraph. This has nothing to do with water heating. It has to do with electrical forces and energy. Work= Volts*chargetrnasfered b. 1/2 m v^2= work done by electicity c. Now use the heat you pointed out. Electrical work= heat to heat water+ heat to make ...
Tuesday, January 26, 2010 at 1:56pm by bobpursley

The sum of the heats gained is zero (some will be negative, as in heat lost). heat gained calorimeter=masscalor*ccu*(Tf-273) heat gained by water= (masswater+massmelted ice)*cw*(tf-0) heat gained by ice= Hf(massice) Heat gained by lead=masslead*clead*(tf-(417+273)) add all ...
Saturday, December 5, 2009 at 8:41pm by bobpursley

Physics - Heat and phase change
8940 J = 2137 calories Melting 20 g of ice will require 1600 calories. That leaves you with 537 cal to heat the liquid water. That is enough to heat 20 g up to 27 C.
Tuesday, March 19, 2013 at 7:47pm by drwls

physics
"over 80g to 8º C" does not make sense. Do you mean ".. is introduced 80 g of aluminum 80g at 8 ºC" ? If so, equate the heat loss of the Al to the heat gain of the water, and solve for the unknown final T. You will need the specific heat of ...
Wednesday, November 24, 2010 at 9:49pm by drwls

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