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how do you do heat energy questions? is it the energy lost? An unpowered 1600 kg object has an upward velocity of 7.0 x 10^3 m s at an altitude of 100 km above the earth. The object reaches a maximum altitude of 400 km. Earth 100 km 400 km v = 7.0 × 10^3 m s What is the heat energy...

Hello! I've attached an image below that shows a simple diagram of my question. I would like to know how to work out the area that I would need for a funnel to increase the air speed from 4.8m/s to 12m/s. The exit would measure 25 by 25, how big would the entrance need to be? I've...

Homework Statement When water freezes, it expands about 9.10%. What would be the pressure increase inside your automobile engine block if the water in it froze? The bulk modulus of ice is 2.00 multiplied by 10^9 N/m2. Homework Equations Delta P=-B*(Delta V)/V The Attempt at a...

I want to hear your opinion on this: Let's say that the universe in time zero consists just of a cloud of matter. Now as the time progresses, and the matter interacts gravitationally, it will gradually collapse into a sphere. Will the entropy of the universe really increase?

Hi Firstly, this is not a homework problem. It's regarding some flow experimental results I have and to understand the results further I am trying to identify possible reasons for the patterns I see. I don't have expertise in thermodynamics hence finding the following problem a bit puzzling...

Hello! I'm trying to make sense of what is probably simple. Imagine I have an IC package that is rated to dissipate at most 1 Watt. The thermal resistance from case to ambient is not known (could maybe be generalized). I have a heatsink that has a thermal resistance of 20°C/W. Can I...

We've heard of the water pipe analogy for electric circuit. It says that the current produces magnetic field and that the "pipe" is irrelevant - only the amp-turns are relevant. So I was wondering, is it possible to increase the amp-turns of a electromagnet by rotating it in the same direction...

1950 the average cost per semester of university in New Zealand was 129$ it is now $5500 per semester, these are averages strange huh? what's it like in America? you always see in movies of high schoolers wanting to get scholarships to go to college because they can't afford it another...

I need to know how can I increase the duty cycle of a pwm. Thank you very much :)

why is it that as the mass of a body increases greater propulsion is needed to move it, according to relativity. i thought that in a vacuum, an object is a lot easier to propel.

Homework Statement Let X_1, X_2,... be independent identically distributed continuous random variables. We call n the first time of increase if X_1>X_2>X_3>...>X_{n-1}<X_n Let N be the time until the first increase. Show that E[N]=e. Homework Equations Given for a discrete random variable...

Hi everyone, According to the equation Power = Force x Velocity or P = mav or a= P/mv, in order to keep say a rocket at constant accelration would require a CONSTANT INCREASE IN ENERGY INPUT PER UNIT TIME. This is somehow problematic to visualize for me. It would mean that accelerating a rocket...

I learn that increase of the beam size of the laser before coupling it to the fiber can increase the coupling efficiency of it. Can I know why is this so? Maybe the fiber is of very small diameter, and the focal lens in front of the fiber can't focus all the laser to this small diameter...

Homework Statement Why does water volume increase when heated past 4 degrees Celsius? 2. The attempt at a solution I know that water molecules move quicker when energy is applied (e.g. heat), but I don't understand why the volume of water must increase. Why can't water molecules just move...

Hi everyone, Today a strange thought came into my mind. We know that the mass of an object increases as it gets closer to the speed of light so it is often stated we would require more and more fuel to accelrate it further. However the mass of the fuel would also increase. What could be done...

Homework Statement when powder or granular solids are piled up. the powder forms a conical pile. the edge of the pile reaches a certain maximum angle with the horizontal, called the angle or repose. A) a pile of coal is found to have an angle of repose of 38% what is the relationship...

Sand is falling into a cone whose height is always 1/2 the diameter of the base. If the sand is falling at a rate of 1/2 cubic meters per min. How fast is the height increasin when the pile is 3 meters high? so far I've drawn my diagram and got this far. Given: h = 1/2 the base dv/dt =...

Hi Can anyone explain in detail about drag increase in supersonic speed Why and how drag increases in Blunt shape nose cone to compare with Sharp nose cone at supersonic speed? Ryan

There is a lot of speculation about why the Earth has not entered into a new ice age, following on from the pattern of glacial cycles recorded in the polar ice cores. It is a possibility that the Earth's tilt towards the Sun actually increased in the recent past. I know this sounds slightly...

A specimen has a potential difference applied, which remains constant throughout. The current through the specimen increases substantially though. Why does it increase? Is this to do with the temperature of the wire increasing and so resistance decreases and the current therefore increases...

Why does the resistance decreases with increase in temp for semi- conductors?

Homework Statement A wave takes 4s to travel form one end of the string to the other. Then the length is increased by 10%. Now how long does a wave take to travel the length of the spring? Homework Equations v = sqrt ( FL/m) F = -kx The Attempt at a Solution If the original...

why? why not?

Homework Statement A frieght train has a mass of 1.5x10^7 kg. The wheels of the locomotive push back on the tracks with a constant net force of 7.5X10^5N, so the tracks push forward on the locomotive with a force of equal magnitude. (ignore aerodynamics and friction) how long would it take...

the question is:- calculate the resultant increase in lenth of a 5m long roof tie rod made of 25mm diameter steel when subject to a tensile load of 80 KN. (assume E=210KM/mm2) does anybody know how to solve this or what the calculation is that i got to use? help apprecited thanks in advance!

Hi Folks, It seems there are some differing opinions in my office with respect to the following. If one is to pump water through a long lenth of 1.75" pipe (16000'), how would you go about predicting the temp rise of the water as it flows along the pipe? From what we have found, when...

hey guys i rebuild diesel engines and i am a facing a very serious problem as i am required to increase a diesel engine hp by at least 20% without adding a turbo charger i tried changing the fuel pump but it only increase 5% which is not enough do you have any idea what i should do ? right...

If you had a sum of money and the question asks that you want a 500% increase, does that mean a yield of 5x the original sum of money or 6x? Someone told me it was 6x but didnt really explain why.

Homework Statement Suppose that the build-up of fatty tissue on the wall of an artery decreased the radius by 10%. By how much would the pressure provided by the heart have to be increased to maintain a constant blood flow? Homework Equations Poiseuille's equation The Attempt at a...

Hi, I'm wondering why the Sun's luminosity has increased over time. I have learned that every star in the main sequence also tend to increase their luminosity but I haven't figured out why. Luminosity is related to star's radius and temperature so does these parameters rise during the...

1. What is the pressure needed to increase the melting temperature by 20 centigrade degrees? Given: Molar Volume (solid) at normal melting temp is 18.92 cm^3 Given: Molar Volume (liquid) at normal melting temp is 19.47 cm^3 Homework Equations delta H (s>l) = T(melting point)* delta S(s>l)...

If so, wasn't it confirmed when we saw an increase in ice levels at the poles this year?

http://www.tgdaily.com/html_tmp/content-view-39973-113.html Also notice the stubborn misunderstanding: Run http://geosci.uchicago.edu/~archer/cgimodels/radiation.html with the basic inputs to get an output radiation of 287.844 W/m2. Now put zero in the CO2 box to get 318.396 W/m2, then...

There is a spaceship in low-earth orbit, at 2000km above the surface of the earth. There are two balls in the spaceship that are dropped. The balls are 1m apart. How long will it take for their separation to increase to 1.01m? Assume that one ball is at 2000km, and the other is at 2000km+1m...

Homework Statement You run a race with your friend. At first you each have the same kinetic energy, but then you find that she is beating you. When you increase your speed by 21%, you are running at the same speed she is. If your mass is 77 kg, what is her mass? Homework Equations...

Hi All, This isn't really a physics course related question or anything (i barely passed secondary school science). But this seems like a place I might be able to find my answer. I'm trying to find the calculation to work out what the increase in speed is of air flowing over a planes...

Homework Statement The radius of a circle is increasing at a constant rate of 0.2 meter per second. What is the rate of increase in the area of the circle at the instant when the circumference of the circle is 20pi meters? Homework Equations The Attempt at a Solution I have no...

A sealed and thermally insulated container of total volume V is divided into two equal volumes by an impermeable wall. The left half of the container is initially occupied by n moles of an ideal gas at temperature T. Which of the following gives the change in entropy of the system when the...

Hi all, I'm a little stumped with how the dielectric increases capacitance. The general solutions all involve using the formulas, but don't really treat it conceptually. I realize that inserting a dielectric decreases field strength, and hence decreases the voltage across the capacitor. But...

not able to pick up a 1 kg iron object off the ground by overcoming the gravitational force between Earth and the object. Consider this : It can pick up a 1 gram (iron) object easily. Then, the increase (from 1gm to 1 kg) would be by a 1000 times. Clearly that increase cannot account for the...

Homework Statement The area of the Earth that is covered by water is 361×10^{6} km^{2}, the volume of the water is 1.4×10^{9} km^{3}, and the mass of the water is 1.4×10^{21} kg. The density of liquid water, as a function of temperature, can be approximated by ρ = 1008 − T /2 kg/m^{3}, where T...

I have two questions about infinity: 1. Can infinity increase? In other words if a number can increase, wasn't it less than infinite before the increase? 2. If a number is finite, must it have a limit? The folks over in cosmology can't get through to me on how the universe can...

Has anybody ever tried adding mirrors around a laser tube cavity where a lot of spontaneous emission can be reflected back into the tube? The idea is like this - if there is a low probablitity of absorption, perhaps the emissions will be induced to occur down the main laser tube where the...

Two loops have current flowing through them (see picture). The top loop lies directly above the bottom one. When the current in the bottom loop is increased, what happens to the top loop's current? Does it increase, decrease, go to zero, doesn't change or it depends on the relative values for...

Six days ago, the Dutch government added a flight fee at Schiphol, the Amsterdam airport, to be used to lower Earth’s atmospheric carbon dioxide (CO2) levels. The Netherlands is one of the four countries that tax carbon put into air in response to advice from the UN-sponsored Intergovernmental...

So they decided to give me an electrical problem at work, and I am completely lost. They're worried about 120V from the wall crossing over onto a 22 AWG wire and causing it to heat up. Is there a way to calculate temperature versus time for this situation? The length of the wire will change...

Homework Statement A hot water heater is operated by using solar power. If the solar collector has an area of 6 m^2, and the power per unit area delivered by sunlight is 1000 W/m^2, how long in hours will it take to increase the temperature of 1 m^3 of water from 20C to 60C? (1 cal=4.186 J)...

Homework Statement how much work is done in increasing the charge on a 3 microfarad capacitor from 300 microcoulombs to 600 microcoulombs? i am supposed to get work W = 0.045 joules Homework Equations capacitance C = Q/V where Q is charge in coulombs, V is electric potential in...

Wavefunction collapse ==> increase in entropy?? I just read an article in Scientific American by Sean Carroll, called something like Does Time Run Backward in Other Universes. In it, he says that the reason wavefunctions only collapse and never un-collapse is because collapsing represents an...

Homework Statement A 40mm diameter bar of aluminium is 2.5m long the bar is has its temperature raised from 20°c to 40°c. Determine the increase in length of the bar in mm. Take the Al = 24 × 10-6 °C-1 How much heat has been transferred into the bar if the SCH = 0.9kj/kg °C Homework...