Thursday

April 17, 2014

April 17, 2014

Number of results: 131,641

**science(1answer)**

4.how does the kinectic energy of a 10,000-kg train traveling at a speed of 10 m/s compare with that of a 2,600-kg compact car traveling twice as fast? A.the train has less kinectic energy than the car. B.the train has more kinectic energy than the car.(I PICK THIS) C.the ...
*Wednesday, January 29, 2014 at 1:37pm by annabelle*

**Science**

How does a light bulb transform electrical energy into radiant energy? The metal filament is heated hot so the the outer electrons on the atoms become exited to higher unstable energy levels, and as they come back to natural levels, light is emitted. THANK YOU SO MUCH!!!
*Wednesday, November 15, 2006 at 6:15pm by Help!*

**Physics**

I'm having a problem understanding a question. "If a man exerts a 200N force while pushing a crate 5.0 m across a floor against a frictional resistance of 40N, how much energy was expended by the person pushing?" I can figure out work done on the box and those sorts of ...
*Tuesday, April 7, 2009 at 10:29pm by Brigid*

**physics**

Lake Erie contains roughly 4.00 1011 m3 of water. (a) How much energy is required to raise the temperature of that volume of water from 9.0°C to 12.0°C? (b) How many years would it take to supply this amount of energy by using the 850-MW exhaust energy of an electric power plant?
*Friday, April 6, 2012 at 5:45am by kevin*

**11th grade Physical Science**

How fast must a 1,000 kg car be moving to have a kinetic energy of: (a) 2.0 x 10^3, (b) 2.0 x 10^5, (c) 1.0 kW x h? How high would you have to lift a 1,000 kg car to give it a potential energy of: (a) 2.0 x 10^3, (b) 2.0 x 10^5, (c) 1.0 kW x h?
*Monday, November 2, 2009 at 6:07pm by britney*

**Physics**

I will be happy to critique your thinking. I am not much inclined to fill in your blanks. on b) number bombs*energy/bomb= comet energy.
*Thursday, February 18, 2010 at 10:43pm by bobpursley*

**renewable energy**

How much total kinetic energy is available in a diesel locomotive weighing 11000 kg travelling at 2.0 km/h?
*Saturday, January 29, 2011 at 11:29am by christian*

**Physics**

A bungee jumper of mass 60 kg jumps from a bridge tied to an elastic rope which becomes taut after he falls 10 m. Consider the jumper when he has fallen another 10 m and is travelling at 15 m/s. Work out how much energy is stored in the rope. Take g=10 m/s^2 and ignore air ...
*Friday, December 17, 2010 at 9:52pm by anon*

**physics**

F = G m Me/r^2 potential energy relative to zero at infinity = -G m Me/r here r = 84600 miles convert that to meters then potential energy lost = Kinetic energy gained G m Me/r = (1/2)m v^2 so v^2 = 2 G Me/r for part b you need m diameter = 2*10^3 so diameter/2 = radius = 1,...
*Monday, May 31, 2010 at 1:06pm by Damon*

**Science**

Matter and energy are related to each other at the atomic level. Energy and matter are also associated to each other at much larger scales of nature. The laws of thermodynamics describe some of the associations between energy and matter as they relate to the Universe.
*Wednesday, September 5, 2007 at 11:05pm by ROFL*

**physics**

A rock is tossed straight up with a velocity of 37.1 m/s. When it returns, it falls into a hole 18.8 m deep. What is the rock's velocity as it hits the bottom of the hole? Responses The gain in kinetic energy equals the loss of potential energy. (1/2) M (V2^ - V1^2) = M g *(18...
*Wednesday, October 8, 2008 at 8:14pm by Vishnu*

**SCIENCE**

Car headlight circuit - is this possible or do I need two separate circuit diagrams? I have the following components: 12 Volt Battery, 1 x Double filament lamp, two switches (assume stay closed when switched). Draw a circuit diagram using these components which would allow: a...
*Saturday, March 17, 2007 at 1:16pm by BIGEYE*

**chem**

How much energy is required to ionize a hydrogen atom in its ground (or lowest energy) state? What wavelength of light contains enough energy in a single photon to ionize a hydrogen atom?
*Monday, October 27, 2008 at 10:09pm by natash*

**Physics**

cg of system does not move originally cg is 1.5 m + 2.5 m = 4 m from shore so (74 + 18) 4 = 74 x + 18 (x+1.5) 368 = 74 x + 18 x + 32.4 335.6 = 92 x x = 3.65 did not get much closer but pushed the canoe back a lot.
*Tuesday, November 16, 2010 at 8:13pm by Damon*

**Science**

Which of the following is a way to improve the efficiency of a heat engine? increase Qh reduce Qh reduce Wnet increase Qc A What are the energies associated with atomic motion called? kinetic energy potential energy bond energy internal energy D A 0.10 kg piece of copper at an...
*Monday, January 23, 2012 at 3:29pm by Lena*

**science**

Marlene's car won't start. She wonders if she is out of gas. She checks the gas gauge and sees that the car has gas. Then she wonders if the battery is dead. She checks the battery and discovers that it is dead. Marlene conclude that her car battery is dead. Accoring to the ...
*Monday, September 6, 2010 at 10:44am by ant*

**microeconomics**

This site may help you answer these questions. http://www.netmba.com/econ/micro/cost/opportunity/ If you post your answers, we'll be glad to comment on them.
*Tuesday, December 11, 2007 at 3:34pm by Ms. Sue*

**physics please help!!**

1. A 26.0-Ω resistor, a 12.0-µF capacitor, and a 17.0-mH inductor are connected in series with a 150-V generator. (a) At what frequency is the current a maximum? 2.A series circuit contains only a resistor and an inductor. The voltage V of the generator is fixed. If R = ...
*Wednesday, March 21, 2012 at 1:51am by linds*

**Chemistry**

Automobile batteries contain sulfuric acid, which is commonly referred to as "battery acid." Calculate the number of grams of sulfuric acid in 0.650 L of battery acid if the solution has a density of 1.28 g/mL and is 38.1% sulfuric acid by mass.
*Sunday, August 18, 2013 at 3:34pm by Anonymous*

**Chemistry**

The equation for photon energy, , is where = 6.626×10−34 (Planck's constant) and = 3.00×108 (the speed of light). What is the wavelength, , of a photon that has an energy of = 3.99×10−19 ? How do go about solving this? I multipled the constant w/ the speed of light...
*Saturday, December 8, 2012 at 2:50am by Trina*

**Chemistry**

The equation for photon energy, , is where = 6.626×10−34 (Planck's constant) and = 3.00×108 (the speed of light). What is the wavelength, , of a photon that has an energy of = 3.99×10−19 ? How do go about solving this? I multipled the constant w/ the speed of light...
*Monday, December 10, 2012 at 12:18am by Trina*

**Chemistry**

The equation for photon energy, , is where = 6.626×10−34 (Planck's constant) and = 3.00×108 (the speed of light). What is the wavelength, , of a photon that has an energy of = 3.99×10−19 ? How do go about solving this? I multipled the constant w/ the speed of light...
*Tuesday, December 11, 2012 at 4:04am by Trina*

**Math**

You want the numbers that are 1000, 10^6 and 10^9 times a trillion. They are called 1 quadrillion (10^12), 1 quintillion (10^15) and one sextillion (10^18)
*Friday, December 12, 2008 at 8:38pm by drwls*

**college/microeconomics**

Just needing to know if I have done the work correctly with this problem: For the total revenue and marginal revenue the answers are: Price $20 Quantity 0 TR 0 MR 0 Price $18 Quantity 1 TR 18 MR 18 Price $16 Quantity 2 TR 32 MR 14 Price $14 Quantity 3 TR 42 MR 10 Price $12 ...
*Sunday, December 6, 2009 at 1:33am by Lorie*

**Microeconomics:**

Just needing to know if I have done the work correctly with this problem: For the total revenue and marginal revenue the answers are: Price $20 Quantity 0 TR 0 MR 0 Price $18 Quantity 1 TR 18 MR 18 Price $16 Quantity 2 TR 32 MR 14 Price $14 Quantity 3 TR 42 MR 10 Price $12 ...
*Sunday, December 6, 2009 at 12:08am by Lorie*

**PHYSICS**

Compute the kinetic energy of the car at 20.2 m/s. (KE = MV^2/2) Divide that energy by 0.181 to get the chemical energy needed to accelerate the car to that speed. Divide the chemical energy requirement by 1.3*10^8 J/gallon to get the numner of gallons needed, X.
*Thursday, April 7, 2011 at 3:40am by drwls*

**Physics/Biohemistry**

If 1/C1+1/C2+1/C3=1/Ceq and Ceq=3.18 mF, then replace the given variables as such: 1/6.54+1/8.19+1/C:unknown=1/3.18 Now it becomes an algebra problem: Multiply both sides of the eqn by 3.18, then you'll have: 3.18/6.54 +3.18/8.18+3.18/Cunknown=1 Simplify: .49+.39+3.18/C=1 1-(....
*Sunday, February 24, 2013 at 10:27pm by Sarah*

**science(chem) Dr.Bob Question from before**

The only reason I asked about the balance is that most analytical balances in use in schools weigh to the nearest 0.1 mg although that may have changed since I retired. There are semi-micro balances that weigh to 5 places and micro-balances that weigh to 6 places but those ...
*Saturday, October 4, 2008 at 12:40am by ~christina~*

**Physics Help!!**

Suppose the kinetic energy of an object moving is 15 J and the potential energy is 25 J at some point in time. Then I measure the potential energy some time later and find it to be 10 J. What is the new kinetic energy?
*Friday, October 8, 2010 at 12:54pm by Liz*

**physics**

Two resistors, one 12Ohms and the other 18 Ohms, are connected in parallel. What is the equivalent resistance of the parallel combination?
*Wednesday, February 17, 2010 at 10:56am by Rony*

**Physics**

According to its design specification, the timer circuit delaying the closing of an elevator door is to have a capacitance of 30.0 µF between two points A and B. (a) When one circuit is being constructed, the inexpensive but durable capacitor installed between these two points...
*Tuesday, October 15, 2013 at 11:33pm by bad at physics*

**Algebra**

r = regular (y axis) e = extra rich (x axis) p = profit = 8 e + 10 r oil limit line (24 max) oil = 2 r + 1 e, when e = 0, r limit is 12 when r = 0, e = 24 so oil line is r = 12 - .5 e butter limit line (18 max) butter = 1 r + 2 e, when e = 0, r limit is 18 when r = 0, e limit ...
*Monday, October 13, 2008 at 7:54pm by Damon*

**phys**

Thermal power is rate of thermal energy. P = (thermal energy) / (time) = Q/t = = m•c•ΔT / t = (m/t) • (c) • (ΔT) Here m/t = 4.9•10^6 kg/s c = specific heat of water = 4186 J/kg•C ΔT = change in the temperature = 0.50 °C Substituting all these values in the ...
*Monday, April 30, 2012 at 1:08am by Elena*

**phys**

Thermal power is rate of thermal energy. P = (thermal energy) / (time) = Q/t = = m•c•ΔT / t = (m/t) • (c) • (ΔT) Here m/t = 4.9•10^6 kg/s c = specific heat of water = 4186 J/kg•C ΔT = change in the temperature = 0.50 °C Substituting all these values in the ...
*Monday, April 30, 2012 at 1:08am by Elena*

**Chemistry Lab**

I'm guessing because you don't have much information. Excited atom makes a.... higher energy..... a lower energy.... emission of a photon.
*Monday, January 17, 2011 at 6:26pm by DrBob222*

**physics**

Potential energy stored in the spring during compression will be (1/2)k(0.1)^2 = 0.5*100*10^-2 = 0.5 J. There will be additional stored gravitational energy of 1 kg*9.8 m/s^2*0.1 m = 1.0 J When the block passes through the equilibrium position, 1.5 will be converted to kinetic...
*Wednesday, November 11, 2009 at 8:50pm by drwls*

**physics**

please check these: A concave mirror with a focal length of 10.0 cm creates a real image 30.0 cm away on its principal axis. How far from the mirror is the corresponding object? a. 20cm b. 15cm c. 7.5cm d. 5.0cm B A diffraction grating that contains 650 472 lines/m is ...
*Friday, March 13, 2009 at 5:46pm by physics*

**physics**

The magnetic field in the region shown below is increasing by 5 T/s. The circuit shown (with R=25 , C=55 µF, dimensions 1 m by 2 m) is inserted into the region as shown. The capacitor is initially uncharged. 1. How long will it take the capacitor to charge to 25% of its final ...
*Saturday, November 12, 2011 at 6:07pm by sonia*

**physics**

The charge of the discharging capacitor, as a function of t, is: Q(t) = Qo* e^(-t/RC) Qo is the initial charge, RC is the time constant, which in this case is 1900*20*10^-6 = 0.038 seconds So, solve 5*10^-6 = 20*10^-6*e^(-t/0.038) ln(1/4) = -t/0.038 t = ?
*Friday, April 1, 2011 at 1:10am by drwls*

**Criminal Justic**

Nope. Here are the first lines of the web site. "ARTICLE 3. OFFENSES AGAINST PERSONS 3.1 BATTERY. (a) Battery is: (1) Intentionally or recklessly causing bodily harm to another person; or (2) Intentionally causing physical contact with another person when done in a rude, ...
*Tuesday, November 13, 2007 at 5:41pm by Ms. Sue*

**Astronomy**

We can calculate the kinetic energy of any moving object with a very simple formula: kinetic energy = 1/2 mv^2 ,where m is the object's mass and v is its velocity or speed. Table Energy Comparisons shows that metabolizing a candy bar releases about 10^6 joules. A- How fast ...
*Tuesday, October 19, 2010 at 4:23pm by Isabelle*

**Micro**

Economic policies are formulated by Congress and the Executive Branch; therefore politics is very much involved. Whether politics is positive or negative on economic policy depends upon your viewpoint.
*Wednesday, June 3, 2009 at 8:38pm by Ms. Sue*

**Chemistry**

Okay so I kinda understand where to put the numbers into the formula but i'm not sure how to calculate the distance so could someone kindly walk me through the problem so i can understand it. Thank you so much. Calculate the amount of energy required for the formation of one ...
*Thursday, November 3, 2011 at 10:08pm by Amanda*

**physics (electricity)**

http://micro.magnet.fsu.edu/electromag/java/faraday/
*Thursday, June 12, 2008 at 9:33pm by DrBob222*

**series and parellel circuits**

ok here we go ... its a series-parellel circuit with 5 resistors. 12 volt battery- wire goes up then one wire branches up at 45 deg with a 10 ohm resistor then down at a 45 deg with a 10 ohm resistor, a second wire branches down at 45 deg with a 20 ohm resistor then up at a 45...
*Monday, May 21, 2012 at 11:47am by Dave*

**the big idea of energy**

The big idea of energy is when a plant uses photosynthesis to get energy from the sun. The animal that eats this plant gets some of that energy transferred. Then the animal that eats that animal gets some of that energy... Understand? Have you done food webs yet? The arrows on...
*Tuesday, December 5, 2006 at 2:18pm by Emzii*

**physics 2**

a certain 12v storage battery with an internal resistance of 12 ohms delivers 80 A when used to crank a gasoline engine. if the battery mass is 20 kg and it has average specific heat of 0.2 kcal/kg K. what is its rise in temperaure during 1 min of cranking the engine. assume ...
*Thursday, February 20, 2014 at 4:44am by Anne*

**science-physics**

Q1)which of these energy resources does not originate from the suns energy?:natural gas,oil,geothermal energy,coal Q2)the burning of fossil fuels does not release? potential energy,light energy,sound energy , heat energy?? Q3)at the moment renewable energy sources generate? ...
*Monday, November 5, 2007 at 4:44pm by elliot*

**physics - electricity **

Not only the size but the age of the battery will affect the circuit's internal resistance. The age also affects the zero-current EMF, especially for Ni-MH and alkaline batteries. If you measure the battery EMF with and without the light bulb in the circuit, and measure the ...
*Sunday, May 23, 2010 at 11:49am by drwls*

**physical science**

Divide the final kinetic energy by 10 seconds. That will be the power in Watts. 746W = 1 horsepower, if you want to convert to those units. 11 m/s is pretty slow for a car. Some humans can run that fast. To take 10 seconds to reach that speed is much too long for highway driving.
*Friday, November 18, 2011 at 1:00am by drwls*

**Physics**

m g h = increase of potential energy 80 * 9.81 * 10^3 = 785*10^3 Joules 785*10^3 = (1/4) total fuel energy burned so total fuel burned = 3.14 * 10^6 Joules 3.14 * 10^6 J / 37*10^6 J/kg = .085 kg
*Saturday, February 15, 2014 at 2:04am by Damon*

**math**

Booth sides must be equal. M+5*log(d/10)=18+5*log(5/10) M=18 d=5
*Thursday, March 31, 2011 at 7:47pm by Anonymous*

**Math**

Number of ways =(18 choose 4)*(10 choose 3) =C(18,4)*C(10,3) with C(n,r) as defined before.
*Sunday, April 17, 2011 at 4:59pm by MathMate*

**Chemistry**

Hoffmans apparatus find out the energy available per mole of water if it is split into h2 and o2 Data 1 mol of gas at NTP is 24.5l 31.2ml of _______ 62.4ml of _______ it looks like this question comes from a lab experiment. You have not provided all the details needed. Were ...
*Wednesday, March 7, 2007 at 2:53am by San*

**physics**

Suppose a 65-kg person can run 1000m in 5min. Assume that each stride is 1.5m long, and with each stride the runner must supply an amount of energy equal to her kinetic energy. How much energy (in food calories) is required to run 1km? Is your answer realistic?
*Sunday, January 29, 2012 at 4:41pm by Hayli*

**science **

a fan uses 150j of mechanical energy, 20j of heat and 75j of sound energy a) what is the total input energy b) what is the total useful output energy c)what is the total wasted energy d) what is the energy efficiency e) what percent of the energy was wasted
*Sunday, December 5, 2010 at 3:57pm by Anonymous*

**Science**

Which of these energy changes takes place in a solar cell? A.Heat energy to light energy B.Light energy to electrical energy C.Electrical energy to heat energy D.Thermal energy to electrical energy C?
*Monday, April 2, 2012 at 5:42pm by Rezu*

**physics**

Friction converts kinetic energy to a. mechanical energy b. potential energy c. nonmechanical energy d. total energy i don't think its B,..
*Saturday, February 21, 2009 at 3:16pm by Bella*

**Science**

Any help would be appreciated! Which of the following is a way to improve the efficiency of a heat engine? increase Qh reduce Qh reduce Wnet increase Qc A What are the energies associated with atomic motion called? kinetic energy potential energy bond energy internal energy D ...
*Wednesday, January 18, 2012 at 5:43pm by Anonymous*

**Science**

Any help would be apreciated! Which of the following is a way to improve the efficiency of a heat engine? increase Qh reduce Qh reduce Wnet increase Qc A What are the energies associated with atomic motion called? kinetic energy potential energy bond energy internal energy D A...
*Thursday, January 19, 2012 at 2:51pm by Anonymous*

**SCI 275**

I chose raw carrots as my vegetable. According to the chart, the energy gained compared to the energy lost was 10% gained to 90% lost. I would say this is clear evidence that humans need to consume foods closer to the bottom of the food chain so a higher amount of the original...
*Monday, November 12, 2007 at 8:35pm by jerry*

**Circuits**

a capacitor charges because of the collection of electrons. The electron's can't move from the wire to the plate instantly, so the capacitor can't charge instantly either. Similarly for inductors. Since electrons have to physically move along the wire, the current is a ...
*Saturday, March 10, 2012 at 1:40am by Steve*

**Physics**

A battery with voltage drop of 120V is connected in a ciruit containing both series and parallel. Moving in a clockwise direction. R1= 3 ohms there is a connection of point A to point B. In between there is a parallel circuit with R2= 10 ohms to R3=2ohms on the top. On the ...
*Wednesday, March 19, 2008 at 10:12pm by Andrea*

**Physics 2**

A(n) 78-Ù resistor and a 68-Ù resistor are connected in series across a battery. The voltage across the 78-Ù resistor is 25 V. What is the voltage across the 68-Ù resistor?
*Thursday, February 16, 2012 at 12:10pm by Anne*

**physical chemistry**

Photon energy = h*c/(wavelength) = 6.62*10^-34 J*s * (3*10^8 m/s)/600*10^-9 m = 3.3*10^-19 J 4*10^-17 J corresponds to 120 photons of that color (orange) light
*Monday, January 30, 2012 at 7:34am by drwls*

**physics**

(a) How much heat (J) flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change(J/K) in entropy due to this heat transfer? (c) How much work (J) is made unavailable, taking the lowest ...
*Thursday, July 25, 2013 at 11:57pm by Justin*

**physics**

(a) How much heat (J) flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change(J/K) in entropy due to this heat transfer? (c) How much work (J) is made unavailable, taking the lowest ...
*Friday, July 26, 2013 at 2:09pm by Justin*

**physics**

(a) How much heat flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change in entropy due to this heat transfer? (c) How much work is made unavailable, taking the lowest temperature to be 18°C?
*Sunday, July 28, 2013 at 3:53pm by Justin*

**physics**

(a) How much heat (J) flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change(J/K) in entropy due to this heat transfer? (c) How much work (J) is made unavailable, taking the lowest ...
*Sunday, July 28, 2013 at 1:33am by Justin*

**physics**

(a) How much heat (J) flows from 1.00 kg of water at 46.0°C when it is placed in contact with 1.00 kg of 18°C water in reaching equilibrium? (b) What is the change(J/K) in entropy due to this heat transfer? (c) How much work (J) is made unavailable, taking the lowest ...
*Sunday, July 28, 2013 at 5:34pm by Justin*

**Physics**

in a compressed spring, energy is in the form of (a) kinetic energy (b) potential energy (c) chemical energy (d) sound energy
*Wednesday, August 18, 2010 at 6:48am by Anonymous*

**Science**

Which one of these is a form of stored energy? A. Heat energy B. Light energy C. Electrical energy D. Chemical Energy D?
*Monday, April 2, 2012 at 4:26pm by Rezu*

**physics**

Lake Erie contains roughly 4.00 multiplied by 1011 m3 of water. (a) How much energy is required to raise the temperature of that volume of water from 11.0°C to 13.0°C? J (b) How many years would it take to supply this amount of energy by using the 950-MW exhaust energy of an ...
*Wednesday, November 17, 2010 at 4:26pm by john*

**Physics**

An object of mass .550kg is lifted from the floor to a height of 3.5m at a constant speed. How much work is done by the lifting force (include units)? b.) How much work is done by the Earth on the object? c.) What is the net work done on the object? d.) What is the change in ...
*Sunday, December 9, 2012 at 8:28pm by Tim*

**Social Studies**

Check this site. http://www.netmba.com/econ/micro/supply/curve/
*Monday, May 4, 2009 at 4:00pm by Ms. Sue*

**physics**

A 20000 kg satellite is launched from the surface of saturn and put into orbit.The satellite is launched at the speed of 27.5 x 10^3 m/s. a)calculte the satellite's total energy. b)Its orbital radius c)If the satellite was shot straight up at the same speed, find its maximum ...
*Monday, June 18, 2012 at 7:14pm by Roger*

**Physics**

A spring with spring constant k=100 (N/m) is at its equilibrium length. a) How much elastic potential energy is stored in the spring? b) The same spring is stretched so that it is 6.0 cm longer than its equilibrium length. How much elastic potential energy is stored in the ...
*Saturday, November 1, 2008 at 3:25pm by DAN*

**Circuit Problem- Physics**

I am trying to do these 2 problems. I'm starting out with the RC Circuit (2nd one): h t t p ://img201.imageshack.us/my.php?image=circuit5ij7.png *delete spaces or link won't load! a) The capacitor acts as a bare wire with no resistance, so: I=V/R=V/(4/5R) b) Capacitor acts as ...
*Sunday, April 13, 2008 at 10:05am by Eileen*

**science**

I guess I'm missing something here...but I've approached this question in every possible angle and im just not getting it! Could somebody point me in the right direction? Here is the question: If the measured net radiation (Q*) for the lawn of your home in August is 700 W/m^2 ...
*Thursday, October 1, 2009 at 8:35pm by Kathleen*

**chemistry**

500 grams of water at 0 degrees C was heated to a boiling in a large pot. how much energy was needed? what was the temperature change and Heat energy
*Monday, May 2, 2011 at 2:46pm by amanda*

**Physics**

1-A car is lifted a certain distance in a service station and therefore has potential energy with respect to the floor. If it were lifted twice as high, how much potential energy would it have? Answer: twice as much 2-Two cars, one twice as heavy as the other, are lifted to ...
*Wednesday, December 9, 2009 at 9:20pm by Emily*

**physics**

A microwave draws 5.0 A when it is connected to a 120 V outlet. If electrical energy costs $0.090 per kW·h, what is the cost of running the microwave for exactly 6 h?
*Wednesday, November 20, 2013 at 10:13am by TT*

**General Chemistry**

An electron in a hydrogen atom relaxes to the n = 4 level, emitting light of 114 THz. What is the value of n for the level in which the electron originated? I am halfway through, but uncertain as to how to simplify the problem to completion. (6.63 x 10^-34 J x s)(1.14 x 10^14 ...
*Thursday, November 1, 2012 at 10:25am by Confused*

**Physics repost clarification**

Find the current in the 10.0 ohm resistor in the drawing (V1 = 21.0 V and R1 = 27.0 ohms). I will attempt to explain the diagram again. The drawing shows 2 parallel lines labelled as follows: A------------B-------------C D------------E-------------F A and D are connected. C ...
*Wednesday, September 12, 2007 at 1:13pm by Jim*

**Algebra**

yes. S = P (1+r)^n 100 = 20 (1+r)^18 (1+r)^18 = 5 18 log (1+r) = log 5 using base 10 logs 18 log(1+r) = .699 log(1+r) = .0388 take antilog 1+r = 1.0935 r = .0935 times 100 = 9.35 %
*Sunday, November 29, 2009 at 9:16pm by Damon*

**English**

1. Two months ago, he was flying to L.A. for a meeting. 2. Two months ago, he was flying to L.A. to have a meeting. (Are both the same?) 3. While he was writing a report, the battery in his computer died. (What other words can we use instead of 'died'?) 4. He couldn't finish ...
*Wednesday, May 1, 2013 at 8:42am by rfvv*

**Please help with 5 math questions**

1. 7r – 7 = 2r + 18 r = –5 r = 5 r = 2.2 r = 1.2 2. 2x + 12 = 18 – x x = 3 x = 10 x = 6 x = 2 3. 8x – 3 = 15x + 18 x = –3 x = 3 x = 2.1 x = .9 4. 6y – 6 = 4y + 16 y = 2.2 y = –2.2 y = 11 y = 5 5. 3(x – 4) = 5(x + 2) x = 11 x = –11 x = 1 x = –1
*Thursday, November 29, 2012 at 3:05pm by Anonymous*

**bcc**

oj in x liters of 30% = .3x oj in (20-x) liters of 10% = .1(20-x) oj in 20 liters of 18% = .18(20) .3x + .1(20-x) = .18(20) .3x + 2 - .1x = 3.6 .2x = 1.6 x = 8 so, 8L of 30% + 12L of 10% = 20L of 18% 8*.3 + 12*.1 = 2.4+1.2 = 3.6 = .18*20
*Wednesday, November 23, 2011 at 8:41pm by Steve*

**Physics**

loss of potential energy = m g h = 18*9.8*4 = 705.6 Joules Kinetic energy at bottom if there were no friction losses also is 705.6 Joules However the actual kinetic energy = (1/2) m v^2 = 9*2.8^2 = 70.6 Joules so 705.6-70.6 = 635 Joules goes into heat
*Saturday, May 14, 2011 at 6:16pm by Damon*

**science**

Which of the following gives off more energy than it absorbs? melting ice, burning propane in a gas heater, sublimation of carbon dioxide to carbon dioxide gas, recharging a car battery
*Tuesday, February 19, 2013 at 1:09pm by lidia*

**English**

How much is the hat? - It is 10 dollars. How much does the hat cost? - It costs 10 dollars. What is the price of the hat? - It is 10 dollars. How much is the price of the hat? - It is 10 dollars. How much do I owe you about the hat? - It is 10 dollars. - You owe me 10 dollars...
*Saturday, December 27, 2008 at 3:08am by John*

**math**

By the way POWER IS NOT ENERGY look in physics book NEVER in math book ! (mathematics text writers do not get this stuff. They do not know the difference between bearing and heading in navigation either) Energy = power * time in this problem Energy is in KW HR and Power is in ...
*Saturday, March 9, 2013 at 6:56pm by Damon*

**Physics Help Please**

Suppose a 65-kg person can run 1000m in 5min. Assume that each stride is 1.5m long, and with each stride the runner must supply an amount of energy equal to her kinetic energy. How much energy (in food calories) is required to run 1km? Is your answer realistic?
*Sunday, January 29, 2012 at 1:42pm by Haylee*

**math**

Find the mean of the following set of numbers. 13, 15, 18, 18, 18, 19, 22, 26, 28, 33 is this correct? 13 15 18 18 18 19 22 26 28 + 33 =210 210/10=21
*Saturday, July 25, 2009 at 6:26pm by unknown*

**Chemistry**

The amount of energy released by burning a fuel source, measured in energy per mass, is called the fuel value. If all the energy obtained from burning 1.25 pounds of propane (fuel value is 11.09 kcal/g) is used to heat 123.0 kg of water at an initial temperature of 18.1 °C, ...
*Friday, November 11, 2011 at 2:32pm by Harley*

**Physics**

I know that when objects are connected and a force is exerted on the connected objects, we treat them as a system with a single acceleration. I was just wondering if objects were piled on top of each other they would still be connected. if a horizontal force was exerted on one...
*Wednesday, August 31, 2011 at 6:53pm by Thara*

**physics**

An electron is released from rest at the negative plate of a parallel plate capacitor. The charge per unit area on each plate is = 2.6 x 10-7 C/m2, and the plates are separated by a distance of 1.4 x 10-2 m. How fast is the electron moving just before it reaches the positive ...
*Saturday, March 19, 2011 at 4:00pm by Amy*

**physics**

In each case, add the translational kinetic energy, (M/2)V^2, to the rotational kinetic energy, (I/2)w^2. I is the moment of intertia about the center of mass and w is the angular velocity. (1a) (M/2)V^2 = (1/2)*0.050*(0.1)^2 = 2.5*10^-4 J (I/2)w^2 = (1/2)(2/5)M*R^2*(V/R)^2...
*Saturday, May 26, 2012 at 6:04am by drwls*

**physics**

If they are connected in series, the circuit is broken by removing one of the bulbs. If they are connected in parallel, there is still a path for electrons to flow after a bulb is removed. Diagrams help.
*Monday, June 29, 2009 at 11:20pm by Marth*

**physics**

what is the electric field at the position 20 cm from Q2 and 60 cm from Q1? Q2=40 micro coulombs Q1=20 micro coulombs Q2 and Q1 are separated by 80 cm
*Wednesday, May 2, 2012 at 7:20pm by quinton*

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