Thermal energy Definition and 199 Threads

Homework Statement A typical coal-fired electric power plant has an efficiency of 39.5%, while a nuclear power plant is 33.5% efficient. (a) How many joules of thermal energy are required by each plant to generate one joule of electrical energy? How much heat does each plant exhaust as...

Hi guys, I saw this problem today and the solutions was not obvious to me, especially because I believe it is not clearly stated. Homework Statement Consider a scheme in which thermal enrgy is extracted from the ocean. Some of the extracted energy is used to perform mechanical work(run the...

Before I begin, Please note that for some reason I don't really grasp physics equations which is odd since I had a A in chemistry but physics just confuses me and also, I am taking this class to prepare me for college. My pencil broke and I didn't think we would have homework of the stuff we...

Thermal energy question?? Homework Statement a 500g iron rod has a temp. of 25 degrees C. how much thermal energy must be added to the rod to double the average kinetic energy of the iron atoms? Homework Equations EH = mc\DeltaT The Attempt at a Solution EH = (0.005 kg)(452 J/kg x...

Homework Statement The question states: You notice a thuderstorm and calculate the Potential Difference between a cloud and a tree to be 150 MV. You know that a lightning bolt delivers 60 C of charge. If the tree only absorbs 5% of the energy of this lightning bolt, with the rest going to...

Homework Statement A 6.0-cm-diameter cylinder of nitrogen gas has a 4.0-cm-thick movable copper piston. The cylinder is oriented vertically, and the air above the piston is evacuated. When the gas temperature is 20 deg C, the piston floats 20 cm above the bottom of the cylinder. -If the...

Homework Statement Proper design of automobile braking systems must account for heat buildup under heaving braking. Calculate the thermal energy dissipated from brakes in a 1260-kg car that descends a 18.5° hill. The car begins braking when its speed is 102 km/h and slows down to a speed of 34...

Hello, I know that something around 65% of the potential energy stored in fuel is lossed in an engine through heat. I am trying to find exactly how its lossed, I know some is through piston friction, and some is lossed through the exhost, but I can't find how much is lossed for each...

Internal and thermal energy vs Temp? Hello I am a layman who is seriously trying to grasp the concepts and principles of physics to understand the workings of the world. I have seen the equations for deriving Internal Energy and Thermal Energy but lack the math to apply them or be sure if...

This is another one that I have given several attempts. Calculate the thermal energy dissipated from brakes in a 1600 kg car that descends a 20 degree hill. The car begins braking when its speed is 95 km/h and slows to a speed of 30 km/h in a distance of 0.27 km measured along the road. I...

Homework Statement An 8.5 kg crate is pulled 5.5 m up a 30degree incline by a rope angled 16degree above the incline. The tension in the rope is 140 N and the crate's coefficient of kinetic friction on the incline is 0.26. What is the increase in thermal energy of the crate and the incline...

Is this statement correct: "Work is done against friction, producing thermal energy"? Thanks

Homework Statement A copper cube mass of 110g is heated to a temperature of 100 Celcius degrees and then rapidly transferred to a well insulated aluminium can of mass 80g containing 200g of water at 10 C degrees . If the final temperature of the cube and water ( after stirring ) is 14 C ...

(SOLVED)Thermodynamics & Thermal Energy Homework Statement a 6.0m X 8m X 3m room contains air at 20 Degrees Celcius Homework Equations What is the room's thermal energy The Attempt at a Solution now i know that oxygen is a diatomic atom so i used E(thermal)= 5/2...

I've read books saying that heat and thermal energy are the same and I've read other books saying they are not the same. I'm confused now. Which of them is right? or maybe they're both right?

One question ask: "Which of the following statements is true? Select the correct answer." a.The quantity of thermal energy exchanged by two bodies in contact is directly proportional to the difference in their temperatures. b.You only need to know the amount of thermal energy a body contains...

Homework Statement You push a block of lead across the floor, applying a horizontal force of 9 N. The block moves at a constant speed. The mass of the block is 1.5 kg and the heat capacity of lead is 130 J/(kg K). After pushing the block a distance of 20 m, you measure its temperature and find...

Homework Statement 140 grams of boiling water (temperature 100° C, heat capacity 4.2 J/gram/K) are poured into an aluminum pan whose mass is 375 grams and initial temperature 25° C (the heat capacity of aluminum is 0.9 J/gram/K). (a) After a short time, what is the temperature of the water...

Brief summary: There is a block that travels down and frictionless curved ramp from A to B and it slides from B to C where the kinetic friction coefficient is 0.25 Question: Determine the thermal energy produced as the block slides from B to C My question: I know for...

a) A 15g bullet is fired at 840m/s into a ballistic pendulum consisting of 24 kg bag of sand. |\ | \ | \ { } | { == } | { } 15 g...

1. for fluids,why is the specific heat capacity at constan pressure is greater than that at constant volume 2. Can some one explain me about the use of air as an insulator in windows, they say it is coz of its low conductivity, how? 3. I've a got confusions about the word " net" that...

How can I design an experiment to determine the thermal energy in a sample of candle wax?

Homework Statement Assuming that the snow is -4 degrees celcius and that the water is dumped at +4 degrees celcius, calculate the amount of heat energy required to operate a metromelt for one hour. Homework Equations Q=mct Q=mLf *little f* The Attempt at a Solution I...

Given the conceivably immense conversion of Earth mass contained in fuel substances, over the past century or so, to heat or other forms of radiant energy that eventually escape into space, is there any known calculation of mass loss attributable to this phenomenon? If so, how much is it...

Homework Statement If 630W is dissipated as thermal energy/heat how much liquid is lost from the body? The Attempt at a Solution I have got through a 3 part problem (re: energy, work etc) and found how much energy is dissipated as heat (630W), but I have no info that leads me to...

Homework Statement A 6.40m by 7.80m by 3.10m room contains air at 20C . What is the room's thermal energy? Homework Equations The Attempt at a Solution I started looking at this problem and to me it is missing information. I know that because it's a homework question it...

I'm new to message.. I have a project about stratifed thermal energy storage... Are there anyone that can help me to guide or give resources about this subject.? In my project: heat is stored in stratified way: there is a thermal layer between hot and cold water. Anyone who knows...

An inductor used in a DC power supply has an inductance of 13H and a resistance of 160 ohms. It carries a current of 0.4 A. What is the stored energy in the magnetic field? At what rate is thermal energy developed in the inductor? L=13H R=160 ohms I=0.4A W = 1/2Li^2 = 1/2(13)(0.4)^2 =...

I'm having some trouble with thermal energy problems. The first question goes like this. 200g of Al at 300 degrees C is placed into a 100g glass Calorimeter with 200g of water at 10 degrees C. What is the final equilibrium temperature of the system. The answer is 57.3 degrees C (the...

Hi all you braniacs out there... I am a final year mechanical engineering student. I need to do a final year project on numerical simulation on melting of phase change material.. I will be required to make use of gambit and fluent CFD software of which i have no idea about... However currently...

Let's say you had a frozen rod of metal and you place it on a warm rod, how does it make the rod colder? And is the warm energy from the other rod transferred to the cold rod or is it unidirectional?

I've got a turntable whose bearing is frictionless rotating at a certain speed. A mass of clay is dropped on to it and sticks a certain distance from the center. I've been able to calculate the new angular speed of the turntable after the lump falls on it, but the follow up question is to...

I cannot get these two questions at all. Can someone teach me how to do these? A spring with k = 47 N/m hangs vertically next to a ruler. The end of the spring is next to the 15 cm mark on the ruler. If a 2.7 kg mass is now attached to the end of the spring, where will the end of the spring...

Question: How long does it take a 1000W electric kettle to bring 1.0L of water to the boiling point if the initial temperature of the water is 15ºC and the kettle is made of 400g of iron? Assume that no water is boiled, that no heat is lost to the surroundings, and that the kettle is 100%...

hello First question - If only force acting on an object is gravitational force then total mechanical energy TME of system is conserved. What about when two objects, each with it's own kinetic energy, collide in an isolated system? Is total mechanical energy of a system conserved (the way...

I was wondering yesterday, the shockwaves and thermal energy created by a dying star as it contracts (if that star is big enough) can create an explosion know as a supernova. so, after the supernova exploded, the star will continue to contract and create shockwaves and thermal energy, since...

I've got a question on thermal energy: Two railroad cars, each of mass 6500 kg and traveling 86 km/h, collide head-on and come to rest. How much thermal energy is produced in this collision? Converted 86 km/h to m/s = 2.389 m/s I assumed that KE converted all into thermal energy: KE =...

Thermal Energy Problem HELP PLEASE! :blushing: :smile: Hi guys I have these 2 thermal energy problems that I keep getting wrong answer, I really want to know the answer and the way to solve it. Thank u very much! 1. The average thermal conductivity of the walls (including windows) and roof...

Hi, My Question: A 22.0 cm- diameter coil consists of 20 turns of circular copper wire 2.6 mm in diameter. A uniform magnetic field, perpendicular to the plane of the coil, changes at a rate of 8.65 x 10^-3 T/S. Determine the rate of which thermal energy is produced. My work: P=...

Hi everyone, None of my professors seem to be able to clearly explain what enthalpy is and its relation to energy. If possible, please confirm or correct my reasoning below: Energy is an abstract (yet quantifiable) term that describes the capacity to cause a change (do work) in a system...

In astronomy class i was told that a grouping of hydrogen must reach 10,000,000K for fusion to occur. Without a sun being a certain size, gravity could never be great enough to generate such high temperatures-brown dwarf. So, could you artificially accelerate gravity (as in future plans for...

im working on building a simple thermal energy storage system...im using water as phase change material.The PCM will be injected into spherical capsules and dropped into a storage tank.Now my problem is that the freezing process initiates only at arnd -12 C.Remember it is under pressure...

[CLPhys1 10.P.042.] Worker Pushes Block A worker pushed a 27 kg block 6.2 m along a level floor at constant speed with a force directed 30° below the horizontal. (a) If the coefficient of kinetic friction is 0.20, what was the work done by the worker's force? (b) What was the increase in...

Seriously Stuck.. A coal fired plant generates 600MW of electric power. The plant uses 4.8 x 10^6 kg of coal a day. The heat of combustion of coal is 3.3 x 10^7 J/kg. The steam that drives the turbines is at a temperature of 573K, and the exhaust water is 310K. 1.) What is the overall...

Does anyone know why I end up with the wrong answer? I went delta q is equal to m c delta t, the derived the equation delta t is equal to delta q divded by mc. I therefore did the math as 232 kJ divided by (10 kg times 4.2 x 10 ^3 j/kg C) and got 9.7 x 10 ^4, when the answer was supposed to...

Does anyone know why I end up with the wrong answer? The question is:

An immersion heater of resistance R converts electrical energy into thermal energy that is transferred to the liquid in which the heater is immersed. If the current in the hearter is I, the thermal energy trasferred to the liquid in time t is? 1) IRt 2) I^2Rt 3) IR^2t 4) IRt^2 5)...

Thermal Energy/ States of Matter- Help! Hey guys! I have been on the road traveling for 6 weeks straight with not much time for schoolwork. Now I am home for 4 days so I have to get to work. I have finished one of my physics tests but wanted some reassurance that the answers are correct- as I...

How does the flow of thermal energy through a closed window illustrate the second law of thermodynamics? Which direction is the flow when it is cold outside? How outside? --Please note this is a textbook question I can't seem to answer.