Sunday

April 20, 2014

April 20, 2014

Number of results: 40,255

**College Physics Homework. Please help!**

A metal bar with a length of 0.30 m and mass of 0.5 kg is free to slide (no friction) on a set of vertical rails. The rails and bar together have a resistance of 500 ohms. The rails lie in a horizontal magnetic field with a strength of 0.04 T. The mass falls under the combined...
*Monday, May 7, 2012 at 7:10pm by Rich*

**physics for scientists and engeneers I**

During a workout, the football players ran up the stadium stairs in 59 s. The stairs are 140 m long and inclined at an angle of 40°. If a typical player has a mass of 103 kg, estimate the average power output on the way up. Ignore friction and air resistance.
*Tuesday, February 15, 2011 at 10:22pm by Johnathon*

**Science**

The sort of things that come to mind are lightness or low density, flexibility (modern plastics), breathable materials, strength (some use kevlar), cushioning (again modern plastics), resistance to wear, resistance to rotting (stability of materials), grip (changes in sole ...
*Thursday, December 3, 2009 at 2:53am by Dr Russ*

**chemistry**

You have 14g water. 190/100=mass/14 solve for mass smmonium nitrate. product mass= (14g+massabove)/.35 Your use of weight and mass is rather loose. weight is not mass, and mass is not weight.
*Saturday, February 19, 2011 at 10:58am by bobpursley*

**Physics **

A lumberjack (mass = 98 kg) is standing at rest on one end of a floating log (mass = 245 kg) that is also at rest. The lumberjack runs to the other end of the log, attaining a velocity of +2.7 m/s relative to the shore, and then hops onto an identical floating log that is ...
*Sunday, November 14, 2010 at 11:52am by Jeffrey *

**physics**

A lumberjack (mass = 98 kg) is standing at rest on one end of a floating log (mass = 200 kg) that is also at rest. The lumberjack runs to the other end of the log, attaining a velocity of +4.0 m/s relative to the shore, and then hops onto an identical floating log that is ...
*Friday, July 19, 2013 at 12:49pm by Anonymous*

**SCIENCE HELP ASAP! :)**

a. what happens to your body when you slam on the brakes? b. gravity pulls down with a constant force, air resistance reduces the net force, so eventually the acceleration toward ground is lessened. When para opens, air resistance is greatly increased, to the point of equaling...
*Friday, April 4, 2014 at 7:56pm by bobpursley*

**College physics**

Find the following potential differences. The magnitude of the potential difference DeltaV1 across the resistor of resistance R1 = 15.0 Ohm. The magnitude of the potential difference DeltaV2 across the resistor of resistance R2 = 45.0 Ohm. The magnitude of the potential ...
*Saturday, July 17, 2010 at 6:59pm by monique*

**physics**

The linear momentum of a body can be calculated by multiplying its mass by the Question 1 options: time during which the mass moves. distance the mass moves. acceleration of the mass. velocity of the mass. Save
*Sunday, February 10, 2013 at 8:59pm by nicole pierre*

**physics**

The linear momentum of a body can be calculated by multiplying its mass by the Question 1 options: time during which the mass moves. distance the mass moves. acceleration of the mass. velocity of the mass. Save
*Sunday, February 10, 2013 at 8:55pm by nicole pierre*

**physics**

At 40,000 ft. air resistance becomes important, as the object will likely reach terminal velocity and greatly increases the time it takes to reach the ground. Also, the horizontal velocity comes into play as the terminal velocity caused by air resistance is actually a terminal...
*Thursday, June 28, 2012 at 12:21am by MathMate*

**physics**

010 (part 1 of 5) 10.0 points A string of 26 identical Christmas tree lights are connected in series to a 120 V source. The string dissipates 63 W. What is the equivalent resistance of the light string? Answer in units of Ω. 011 (part 2 of 5) 10.0 points What is the ...
*Thursday, March 3, 2011 at 8:33pm by Anonymous*

**Physics**

A 0.25 mass is located on the outer edge of a wheel of radius 0.75 m that is turning at a rate of 2 revs/s. Determine the following: 1) The period of the mass 2) The angular speed of the mass in rad/s c) The tangential speed of the mass d) The centripetal acceleration of the ...
*Sunday, December 13, 2009 at 7:11pm by Monika*

**Chemistry-PLease help!**

PV=nRT density =mass/volume =mass/V n=mass/M where M = molar mass PV=mass R T /M rearrange PM/RT=mass/V=density
*Wednesday, December 8, 2010 at 7:50am by Dr Russ*

**electricity**

(a) I = V/R where R = Rb + Ri = (10 + 2)*10^3 = 12,000 ohms Rb = body resistance Ri = power supply internal resistance (b) I^2*Rb (c) Require that V/(Rb + Ri) < 10^-3 A Solve for Ri
*Friday, June 10, 2011 at 1:31am by drwls*

**conceptual physics**

The linear momentum of a body can be calculated by multiplying its mass by the Question 1 options: time during which the mass moves. distance the mass moves. acceleration of the mass. velocity of the mass. Save
*Sunday, February 10, 2013 at 11:39pm by nicole pierre*

**BASIC ELEC**

1. Conductors 2. Load(Resistor, Lamp, etc.). 3. Switch. 4. Circuit Breaker. 5. Power Supply. The 4 conductors are correct. Four Factors That Affect Resistance: 1. Voltage. 2. Current. 3. Power. 4. Tempeature. Two Ways to Decrease Current: 1. Decrease supply voltage. 2. ...
*Tuesday, January 10, 2012 at 6:11pm by Henry*

**physics**

could someone PLEASEE help me? Ive procrastinated and i'm really desperate... I'm supposed to teach the class about "relativistic momentum and mass" in terms of special theory of relativeity. i looked up infomation on google, but i dont understnad because its mostly university...
*Monday, April 23, 2007 at 5:24pm by kay*

**energy conversion**

A 5hp 230volt shunt motor takes 18 amp when operating at full load. The Shunt-field resistance is 115ohms and the armature resistance is 0.25 ohm. calculate the value of the starter resistor if the armature current is limited to 1.5 times the rated value at the starting ...
*Monday, September 20, 2010 at 3:04am by baskuuugin*

**chemistry**

This is more electrical than chemical and I have no idea what 16, 23, and 34 resistors are. Is that ohms or some other unit? If ohms, then The total resistance of the circuit, ignoring the internal resistance of the batter and other wiring, is the sum of the three resistors; i...
*Saturday, December 3, 2011 at 10:35pm by DrBob222*

**math**

A 300 kVA transformer has a primary winding resistance of 0.4 Ω and a secondary winding resistance of 0.0015 Ω. The iron loss is 2 kW and the primary and secondary voltages are 4 kV and 200 V respectively. If the power factor of the load is 0.78, determine the ...
*Saturday, May 18, 2013 at 1:44pm by Anonymous*

**Physics**

The drag coefficient = 0.354 The mass of car = 1200 kg rolling resistance = 180 N Air density = 1.181 kg m^-3 Frontal area = 1.88 m^2 What is the deceleration at a speed of 82 km h^-1 when the car is taken up to high speed and then allowed to coast down on a level road.
*Saturday, August 18, 2012 at 9:15pm by Alex*

**physics**

3. Calculate the magnitude of the force required to cause an anterior dislocation of the glenohumeral joint given that he force has a lever arm of 52 cm, the maximum magnitude of the resistance force is 1080 N and the resistance force has a lever arm of 4.3 cm.
*Wednesday, December 5, 2012 at 11:44am by dmkp*

**physics**

3. Calculate the magnitude of the force required to cause an anterior dislocation of the glenohumeral joint given that he force has a lever arm of 52 cm, the maximum magnitude of the resistance force is 1080 N and the resistance force has a lever arm of 4.3 cm.
*Wednesday, December 5, 2012 at 11:44am by dmkp*

**physics**

Calculate the magnitude of the force required to cause an anterior dislocation of the glenohumeral joint given that he force has a lever arm of 52 cm, the maximum magnitude of the resistance force is 1080 N and the resistance force has a lever arm of 4.3 cm.
*Friday, December 7, 2012 at 6:35am by dmkp*

**biomechanics**

Calculate the magnitude of the force required to cause an anterior dislocation of the glenohumeral joint given that he force has a lever arm of 52 cm, the maximum magnitude of the resistance force is 1080 N and the resistance force has a lever arm of 4.3 cm.
*Wednesday, December 12, 2012 at 7:44am by dmkp*

**physics**

Xc =< 0.1(Rs+Rl). = The capacitor's Reactance. Rs = The source resistance. Rl = The load resistance. Cc = 1/(W*Xc) = 1/(W*0.1(Rs+Rl)) = Coupling capacitor in Farads. W = 2pi*F. F = Frequency in Hertz. Rs and Rl in ohms.
*Tuesday, March 26, 2013 at 10:52pm by Henry*

**science**

When you first release the contraption and the egg, the force of gravity is pulling on the egg as it going to the ground. Which the force of the air resistance is trying to push up on the egg. The net force of the falling egg is equal to the air resistance. As the speed is ...
*Tuesday, April 13, 2010 at 10:08pm by Anonymous*

**Physics**

A man throws a rock of mass m = 0.310 kg straight up into the air. In this process, his arm does a total amount of work Wnet = 105 J on the rock. Calculate the maximum distance, h, above the man's throwing hand that the rock will travel. Neglect air resistance.
*Sunday, May 27, 2012 at 9:05pm by James*

**heat transfer**

The addition of insulation in some cases may reduce thermal resistance due to the reduction in convective thermal resistance because of increase in surface area as in case of cylinder and sphere. It may be shown that the thermal resistance actually decreases and then increases...
*Friday, September 7, 2012 at 2:40am by paper kro*

**Physics**

Two circuits (the figure below) are constructed using identical, ideal batteries (emf = E ) and identical lightbulbs (resistance = R). If each bulb in circuit 1 dissipates 4.00 W of power, how much power does each bulb in circuit 2 dissipate? Ignore changes in the resistance ...
*Thursday, February 16, 2012 at 3:49pm by jason*

**CHEMISTRY**

Let X = mass Ag Let Y = mass Ba ======================== One equation you can use is: X(molar mass Ag2CrO4/2*atomic mass Ag) + Y(molar mass BaCrO4/atomic mass Ba) = 0.944 Do you have the mass of the sample of nitrates you used? I hope so. Then the second equation would be as ...
*Monday, January 28, 2008 at 3:48pm by DrBob222*

**science**

Assume you had 100cm^3 of pennies. Then you would have a mass of 91.768*densityzinc, and a mass of 8.232*density copper. Add those to get the total mass. You know the mass, so find density (mass/volume)
*Tuesday, August 18, 2009 at 10:53pm by bobpursley*

**Physics**

a) mass, m = 0.02 kg Distance, S = 10 cm = 0.01 m initial velocity, u = 500 m/s final velocity, v = 200 m/s Acceleration = (v²-u²)/2S m/s² b) v=u+at solve for t. c) Time to travel 10 cm without resistance, t0 = S/u
*Sunday, December 5, 2010 at 7:01am by MathMate*

**Physics**

Well, nothing would prevent you from doing that :) To analyze what would happen, just draw the circuit diagram where you represent each battery as a fictitious ideal emf and a resistor with resistance equal to the batteries internal resistance in series. What you find is that ...
*Monday, March 10, 2008 at 12:23pm by Count Iblis*

**Physics**

The coil of wire in a galvanometer has a resistance of RC = 78.0 Ù. The galvanometer exhibits a full-scale deflection when the current through it is 0.440 mA. A resistor is connected in series with this combination so as to produce a voltmeter. The voltmeter is to have a full-...
*Sunday, February 24, 2013 at 9:39pm by Don*

**Physics**

A car of mass 900.0 kg accelerates away from an intersection on a horizontal road. When the car speed is 49.7 km/hr (13.8 m/s), the net power which the engine supplies is 4300.0 W (in addition to the extra power required to make up for air resistance and friction). Calculate ...
*Thursday, January 2, 2014 at 4:05pm by Sam*

**Physics**

A car of mass 900.0 kg accelerates away from an intersection on a horizontal road. When the car speed is 49.7 km/hr (13.8 m/s), the net power which the engine supplies is 4300.0 W (in addition to the extra power required to make up for air resistance and friction). Calculate ...
*Thursday, January 2, 2014 at 6:31pm by Adam*

**physics**

A truck engine transmits 28.0 { kW} (37.5 hp) to the driving wheels when the truck is traveling at a constant velocity of magnitude 60.0km/h( 37.3mi/h) on a level road. 1.Assume that 65% of the resisting force is due to rolling friction and the remainder is due to air ...
*Sunday, April 4, 2010 at 3:06pm by mohd*

**physics**

The length and diameter of the platinum wire used in a thermometer are often chosen so that the resistance of the device at around 0 ºC is 100 ohms. Such a sensor is a called a PT100 sensor, and its resistance changes by approximately 0.4 ohms per degree Celsius. Using a ...
*Tuesday, January 29, 2013 at 5:22am by Elena*

**Physics**

A child riding a bicycle has a total mass of 40kg. The child approaches the top of a hill that is 10m high and 100m long at 5m/s. If the force of friction between the bicycle and the hill is 20N, what is the child's velocity at the bottom of the hill? (Assume no air resistance...
*Sunday, November 15, 2009 at 7:41pm by Monique*

**Physics**

If a wire of resistance R, resistivity ñ "roe", length L, and cross sectional area A, had its length doubled and radius halved, what would be the ratio of R'/R. Where R' is the new resistance of the wire. I thought it would be 4 times R, giving the ratio of 4R:R' However, I ...
*Thursday, July 26, 2012 at 10:14pm by Lauren*

**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*

**physics**

A .1kg mass is located on the line between a 5kg mass and a 10kg mass. It is 4m to the right of the 5kg mass and 6m go the left of the 10kg mass. What is the magnitude and direction of the net force on the .1kg mass?
*Thursday, November 17, 2011 at 8:13pm by Jen*

**Physics**

(1) 45 micro coulombs of charge is passed through a wire in 35 seconds. How many electrons does this represent? What is the current in the wire? (2) A piece of copper wire has a resistance of 5 Ohms at 20 degrees celsius. If another piece of copper wire at 0 degrees celsius is...
*Monday, May 4, 2009 at 1:54pm by Bob*

**physics**

A 5kg ball is thrown upward with an initial speed of 30m/s. Suppose there is a constant air resistance of 25N opposing the motion during its entire up and down path. How much work was done by air resistance during the entire path up and down. Wfric= -f X (-30)(62)= -1860J is ...
*Monday, December 20, 2010 at 9:19pm by dipset*

**Physics**

A ball of mass 0.3 kg, initially at rest, is projected from ground level toward a wall that is 27.0 m away. The ball's velocity the moment it is projected is 75.0 m/s at 60° relative to the horizontal, and the wall is 11.0 m high. During its flight, the ball impacts nothing ...
*Thursday, March 7, 2013 at 7:15pm by Jalen*

**science**

A car of mass 1500 kg accelerates up a hill of incline 8 degrees, increasing its speed from 4 ms to 16 ms over a distance of 90m. Assuming a total frictional resistance of 1000 N, calculte: a) the tractive effort between the wheels and the road surface b)the work done during ...
*Sunday, January 26, 2014 at 11:28am by Robert*

**calculus help check and help **

if an object with mass m is dropped from rest, one model for its speed v after t seconds, taking air resistance into account is v= mg/c(1-e^(-ct/m)) where g is the acceleration due to gravity and c is a positive constant describing air resistance. a) calculate lim t->...
*Wednesday, April 16, 2014 at 5:01pm by JuYoung*

**physics**

a particle drops from the height 500m with the initial velocity at rest, and it goes into the water. a particle has a mass of 1kg. draw graphs a-t, v-t, and s-t until 10 second after it hits the water. consider the air and water resistance is measured as F air=.005v^2 N and F ...
*Monday, May 2, 2011 at 6:30am by mike*

**physics**

Each of the four circuits in the drawing consists of a single resistor whose resistance is either R or 2R, and a single battery whose voltage is either V or 2V. The unit of voltage in each circuit is V = 10 V and the unit of resistance is R = 8 Ω. Determine (a) the power ...
*Thursday, February 14, 2013 at 6:02am by Anonymous*

**Physics**

At the low point in its swing, a pendulum bob with a mass of 0.2 kg has a velocity of 4 m/s What is the Kinetic at the low point? and Ignoring air resistance how high will the bob swing above the low point before reversing direction?
*Friday, February 15, 2013 at 2:00pm by Laura*

**math**

A skydiver with a weight of 185 lbs is falling. At a certain moment the force of air resistance on the sky diver is 145 lbs. What is the skydiver's acceleration at this moment? (Hint: Remember that the weight of an object is given by mg.) AND When the skydiver reaches a ...
*Sunday, September 23, 2012 at 1:52pm by kara*

**Calculus**

If V volts are measured across a resistance of R ohms in a circuit carrying a current of I amperes, V=IR. At a certain instant, the voltage is 250 and is increasing at a rate of 4 volts/min, while the current is 0.5 AMP and is increasing at a rate of 0.01 amp/min. Find the ...
*Thursday, February 28, 2013 at 11:00am by Trevor*

**PHYSICS H**

suppose an elephant and a feather fall from a skyscraper. in the presence of air resistance, the elephant would fall faster because...list all that apply. a) acceleration of gravity is greatest for the elephant b) elephant experiences a smaller air resis. force c) the greater ...
*Tuesday, October 23, 2012 at 2:18pm by kyle*

**Jenish**

a) Since power = V^2/R , if R were constant the power would decrease by a factor (105/117)^2 = 0.0805. This is a 19.5% reduction in power b) The electric heater wire in a hair dryer does not have a constant resistance with temperature. The resistance will be somewhat lower at ...
*Saturday, February 16, 2008 at 2:43am by drwls*

**Science**

A battery of emf 12v nd internal resistance (r) 1.5votls is connected to an external resistance (R) of 3ohms. (1.) Cal, the current flowing in the circuit. (2,) the p.d draw across the 3ohms resitor and the internal resirtance. (3) determine Voltage of the battery and comment ...
*Saturday, May 21, 2011 at 6:25pm by Usoro*

**Chemistry**

mass proton x 120 = ?p mass neutron x (29?-120) = ?n total mass = ?p+?n x %mass def/100 = ?mass isotope. (mass isotope x %/100) + (mass isotope x %/100) ........etc for all the isotopes. The total is the average atomic mass.
*Saturday, October 13, 2012 at 11:19pm by DrBob222*

**physics**

ANSWER IS 1CM. SOLUTION TOTAL MECHANICAL ENERGY= TO K.E+P.E =0.5MASS VSQUARE+MASS GH K.E TOP +P.E TOP= K.E BOTTOM +P.E BOTTOM 0+0.5MVSQUARE=M(9.81)(0.1) V=1.400 MASS M/SEC 90% LOSE OF ENERGY M.E=MASS(G)(H) @ THE TOP M.E=MASS (9.81)(0.1) M.E=MASS 0.981 REDUCTION OF 90% DURING ...
*Wednesday, February 6, 2013 at 3:25am by EDSEL*

**physics**

The movement cant be horizontal, but is always at some angle. Knowing that angle and keeping it uniform is important. Timer is one, of course, and the counting. Wondering if you timed one rev, or timed say ten revs and then divided by ten...there is a big difference in error. ...
*Saturday, September 29, 2007 at 5:56pm by bobpursley*

**chemistry**

Note: weigh is spelled without the final t. 43.772 g = mass KClO3 mixture + tube -41. 960 = mass tube -------------- ?? = mass KClO3 initially. 43.772 = mass KClO3 mixtur + tube -43.332 = mass after final heating --------------- ?? = loss in mass = mass oxygen %oxygen = (mass ...
*Tuesday, October 4, 2011 at 12:37pm by DrBob222*

**Physics**

two point masses are located in the same plane. the distance from mass 1 to the center of mass is 3.0m. The distance from mass 2 to the center of mass is 1.0m. What is m1/m2, the ratio of mass 1 to mass 2?
*Tuesday, March 29, 2011 at 5:02pm by Jacob*

**Chemistry**

Look up the mass for each of these elements on a periodic table. Mass of Carbon + two times the mass of sulfur. 6 times the mass of Carbon + 12 times the mass of Hydrogen + 6 times the mass of oxygen.
*Monday, March 4, 2013 at 4:35pm by Dr. Jane*

**Physics-Please help**

I need a little direction with this question:If someone could provide the correct formula, I think I divide each reistor by 12V but I'm not sure. To find total resistance, do I just add the reciprocals? Three resistors connected in parallel have individual values of 4.0, 6.0 ...
*Thursday, March 24, 2011 at 2:13pm by Sally*

**physics em**

The resistance of the bulb at operating temperature is R = V^2/P = 137.1 ohms. If it is in series with 8.2 ohm contact resistance, the voltage applied to the bulb filament is reduced to 120*(137.1/145.3) = 113.2 V, and the power dissipated INE THE BULB is reduced to V^2/R = (...
*Monday, March 10, 2008 at 3:12pm by drwls*

**College Physics**

The upside down U is an omega and means ohms. A) The current though each resistor is V/R. Each has the same value of V (100 V) across it. B) The resistance of the two resistors add up to an effective circuit resistance of Rtotal = 100 ohms. I = V/Rtotal use that value of I for...
*Sunday, February 7, 2010 at 12:18am by drwls*

**Chemistry-please help**

The relative mass of a proton is 1 and the relative mass of a neutron is 1. 1)Why do we use the term "relative mass" instead of mass? Is it because the mass of a proton is compared to the mass of a carbon-12 atom? 2) Can we say that the relative mass of an atom is 2 (proton+...
*Tuesday, January 20, 2009 at 2:28pm by janice*

**Physics**

A rock of mass m and a rock of mass 2m are both released from rest at the same height and fee no air resistance as they fall. Which statements about these rocks are true? (there may be more than one!) EXPLAIN HOW YOU KNOW THEY ARE TRUE AND EXPLAIN WHY THE OTHERS ARE WRONG!!!(a...
*Thursday, March 24, 2011 at 1:46pm by Sam Potter*

**Physics**

The speed of a bobsled is increasing because it has an acceleration of 2.4 m/s2. At a given instant in time, the forces resisting the motion, including kinetic friction and air resistance, total 450 N. The mass of the bobsled and its riders is 235 kg. (a) What is the magnitude...
*Wednesday, October 3, 2012 at 10:34pm by Donald*

**PHYSICS**

express dissipated power in terms of voltage and resistance. express dissipated power in terms of current and resistance
*Sunday, September 8, 2013 at 5:01pm by preya*

**College Physics**

Resistance of wire is proportional to length in this case (same area for both wires). For equal voltages on both wires, current is inversely proportional to resistance. Current is therefore also inversely proportional to length.
*Saturday, February 6, 2010 at 11:31pm by drwls*

**Physics**

A large number of AA batteries with emf E=1.5 V and resistors with resistance R form an infinite circuit . The internal resistance of the batteries is r. Thevenin's theorem tells us that this infinite circuit can be replaced by a single source with emf E_eq, connected in ...
*Saturday, July 13, 2013 at 8:34am by Steve*

**Dynamics**

Fundamental Problem 15.12 The cannon and support without a projectile have a mass of 250 kg. If a 20 kg projectile is fired from the cannon with a velocity of 400 m/s , measured relative to the cannon, determine the speed of the projectile as it leaves the barrel of the cannon...
*Wednesday, September 21, 2011 at 1:21am by Kate*

**Physics**

forcenetdown= mass*a mgSinTheta-mu*mg*cosTheta=mass*a but notice mass divides out, so acceleration is independent of mass, if it is moving.
*Wednesday, November 3, 2010 at 5:22pm by bobpursley*

**science**

An EMF will be induced in the ring due to the changing magnetic field passing through it. This will cause an "eddy" current to flow back and forth in the ring, resulting is resistive heating. Since the induced AC EMF is constant, the power absorbed and deposited in the ring (V...
*Sunday, May 2, 2010 at 5:57am by drwls*

**physics**

The drawing shows a copper wire (negligible resistance) bentinto a circular shape with a radius of 0.48 m. The radial sectionBC is fixed in place, while the copper bar ACsweeps around at an angular speed of 16 rad/s. The bar makeselectrical contact with the wire at all times. ...
*Monday, March 12, 2012 at 1:03am by Daniel*

**physics**

A 50 V battery has an internal resistance r. 1 A 50 V r 55 Ω 66 Ω internal resistance What is the value of r? Answer in units of Ω 009 (part 2 of 2) 10.0 points Determine the magnitude of the current through the 66 Ω resistor in the upper left of the ...
*Wednesday, February 20, 2013 at 11:16pm by Anonymous*

**physics help pls**

large number of AA batteries with emf E=1.5 V and resistors with resistance R form an infinite circuit . The internal resistance of the batteries is r. Thevenin's theorem tells us that this infinite circuit can be replaced by a single source with emf E_eq, connected in series...
*Sunday, July 14, 2013 at 5:54am by Steve*

**PHYSICS**

An automobile battery has an emf of 12.6 V and an internal resistance of 0.0500 . The headlights together present equivalent resistance 5.60 (assumed constant). (a) What is the potential difference across the headlight bulbs when they are the only load on the battery? V (b) ...
*Friday, September 6, 2013 at 12:29am by priya*

**College Physics**

A record company executive is on his way to a TV interview and is carrying a promotional CD in his briefcase. The mass of the briefcase and its contents is 4.00 kg. The executive realizes that he is going to be late. Starting from rest, he starts to run, reaching a speed of 2....
*Tuesday, October 13, 2009 at 6:33pm by Megan*

**Physics**

A voltmeter of internal resistance of 5000 Ω is connected across the poles of a battery of internal resistance 0.20 Ω. The voltmeter reads 1.4993 volts. What is the actual zero-current emf of the battery? Would this formula be I = V/(r+R) = 1.4993/(5000+0.20)?
*Monday, March 22, 2010 at 12:59am by Selma*

**Physics**

A trapeze artist, starting from rest, swings downward on the bar, lets go at the bottom of the swing, and falls freely to the net. An assistant, standing on the same platform as the trapeze artist, jumps from rest straight downward. Friction and air resistance are negligible...
*Tuesday, May 8, 2007 at 9:28am by Papito*

**Chemistry**

I need to find the average molar mass of an unknown element. The atomic mass is 120; the mass numbers of isotopes are 295, 296, 297, 298 and 299; the percent of each isotope is 2.356%, 4.325%, 15.652%, 48.452% and 29.215%. The mass of the neutron is 1.67262164x10^-24g and the ...
*Saturday, October 13, 2012 at 11:19pm by Joe*

**Chemistry**

I need to find the average molar mass of an unknown element. The atomic mass is 120; the mass numbers of isotopes are 295, 296, 297, 298 and 299; the percent of each isotope is 2.356%, 4.325%, 15.652%, 48.452% and 29.215%. The mass of the neutron is 1.67262164x10^-24g and the ...
*Sunday, October 14, 2012 at 12:05am by Joe*

**AP Chemistry**

What fraction, F, of the mass of a Fe2O3 molecule is FE ? total mass of molecule = 2(atomic mass Fe)+3(atomic mass O) mass of Fe in that molecule = 2 (atomic mass Fe) so F = 2(atomic mass Fe)/[ the sum ] then Mass Fe = 10.1 * F and percent = (Mass Fe/44.6)100
*Monday, September 2, 2013 at 6:58pm by Damon*

**chemistry**

1.7839g = mass BaCl2.2H2O + KCl -1.5623g = mass after heating ------------ 0.2216g = mass H2O driven off. mass BaCl2.2H2O = 0.2216 x (molar mass BaCl2.2H2O/2*molar mass H2O) = ? Then 1.7839-mass BaCl2.2H2O = mass KCl. I will leave it for you to finish the problem. Post your ...
*Sunday, February 24, 2013 at 2:24pm by DrBob222*

**physics**

how can i calculate the slope of the best-fit line in a length v.s. resistance(x=length;y=resistance) graph where the plotted points are: (5.1,1.6)(11.0,3.8)(16.0,4.5)(18.0,5.9)(23.0,7.5)? Personally, I would graph the points, and draw a best fit line, then measure the slope ...
*Sunday, May 20, 2007 at 6:13pm by koeit*

**Physics**

A 120.0 volt motor draws a current of 7.60 A when running at normal speed. The resistance of the armature wire is 0.610. (a) Determine the back emf generated by the motor. 115.364 V (b) What is the current at the instant when the motor is just turned on and has not begun to ...
*Tuesday, October 9, 2007 at 3:28pm by Mary*

**college physics**

The air resistance is not constant, but increases in proportion to V^2. The best you can do is compute an average air resistance during the fall. You would do this by computing the work done against air friction and dividing it by the distance fallen. Friction work = M g H - (...
*Monday, March 1, 2010 at 9:56am by drwls*

**physics**

If R1 and R2 be the two resistances connected in (a)series, then equivalent resistance=R1+R2 (b)parallel, then equivalent resistance=(R1*R2)/(R1+R2)
*Wednesday, August 5, 2009 at 10:14am by Aayush*

**Physics 103**

You have two light bulbs: One with resistance R1 and one resistance R2. Assume R1 > R2. A) Which bulb is brighter if connected in series. Explain. B)Which bulb is brighter if connected in parallel. Explain.
*Sunday, February 7, 2010 at 12:22am by Linda*

**physics**

An artillery shell is fired at an angle of 48.2 degrees above the horizontal ground with an initial speed of 1530 m/s. THe acceleration of gravity is 9.8 m/s^2. Find the total time and flight of the shell,neglecting air resistance.Answer in units of minutes. Find its ...
*Thursday, June 23, 2011 at 12:18am by alexa*

**Physics**

An artillery shell is fired at an angle of 55.7◦ above the horizontal ground with an initial speed of 1690 m/s. The acceleration of gravity is 9.8 m/s^2. a.Find the total time of flight of the shell, neglecting air resistance. Answer in units of min. b.Find its ...
*Sunday, February 16, 2014 at 4:17pm by Fabricus*

**physics**

You have two simultaneous equations to solve, and they depend upon the resisitivity and the density, which you will have to look up. 1)0.500 ohms = (resistivity)*L/(pi*D^2/4) 2)0.900 g = (density)*L*pi*(D^2/4) I suggest using centimeter, g/cm^3 and ohm-cm units. The product of...
*Friday, September 17, 2010 at 10:10pm by drwls*

**Physics**

What is the resistance of a coffee maker that draws a current of 5.0A from 117V source? What resistance would have to be added in parallel with the same coffee maker to increase the current to 15.0A? Okay, so for the first part I got 23.4 Ohms since R=V/I, but I don't really ...
*Wednesday, December 10, 2008 at 8:41pm by Lana*

**Chemistry**

How would you set up for the percent? %Cl = [(Mass AgCl ppt)*(1 mol AgCl/molar mass AgCl)*(atomic mass Cl^-/1 mol Cl^-)/mass sample]*100 = ?? Now you want mass ppt to equal %Cl. It looks confusing on the board but write it out on a sheet of paper and you will see it. Solve the...
*Thursday, April 23, 2009 at 12:31am by DrBob222*

**chemistry**

thank you for any help possible. Given a Mass Percent 13.3% and a Mass Solvent of 325.2 g, find Mass of Solute and Mass of Solution. Mass%=13.3% Mass solvent= 325.2g solve for the Mass solute and Mass solution. This is all the information I am given.
*Sunday, December 4, 2011 at 6:44am by ben 16*

**Science**

No. Mass is the mass (weight in common terms) of an individual object, whether it be an atom, molecule, or a dinner plate (or a person). Molar mass is the mass of 1 mol of material.
*Monday, December 10, 2007 at 5:29pm by DrBob222*

**Physics**

A projectile mass of 0.500 kg is shot straight up with an initial speed of 28.0 m/s. A. How high would it go if there were no air friction? I got this answer, it is 40 m. B. If the projectile rises to a maximum height of only 34.0 m, determine the magnitude of the average ...
*Wednesday, March 7, 2012 at 11:20pm by Mariah*

**physics**

We know how to calculate the total resistance of the cylindrical conductor given its length, radius, and resistivity. But how do we calculate the equivalent resistance when the resistivity is not constant? For example, say the resistivity at a particular point at a distance x ...
*Monday, March 11, 2013 at 10:56am by abcd*

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