Friday

October 31, 2014

October 31, 2014

Total # Posts: 43

**Chemistry**

A small hole in the wing of a space shuttle requires a 12.8cm^2 patch. What is the patch's area in square kilometers (km^2)? if the patching material costs NASA 3.21/in^2, what is the cost of the patch?
*September 6, 2010*

**College Physics**

An electron travels at a speed of 0.700c. What is its kinetic and total energy? I got, but this is not right. K , E =3.27×10−14,1.14×10−13 J Thanks for your help
*April 30, 2010*

**college physics**

Sirius is about 9.0 light-years from Earth. To reach the star by spaceship in 10 years (ship time), how fast must you travel? How long would the trip take according to an Earth-based observer? How far is the trip according to you?
*April 30, 2010*

**colleg physics**

Sirius is about 9.0 light-years from Earth. To reach the star by spaceship in 10 years (ship time), how fast must you travel? How long would the trip take according to an Earth-based observer? How far is the trip according to you?
*April 30, 2010*

**College Physics**

Sirius is about 9.0 light-years from Earth. To reach the star by spaceship in 10 years (ship time), how fast must you travel? How long would the trip take according to an Earth-based observer? How far is the trip according to you?
*April 25, 2010*

**Physics**

A solar cell is designed to have a nonreflective film of a transparent material for a wavelength of 600 nm. Will the thickness of the film depend on the index of refraction of the underlying material in the solar cell? nsolar > nfilm and nfilm = 1.25, what is the minimum ...
*April 22, 2010*

**Physics**

A telescope has a magnification of 20 and consists of two converging lenses, the objective and the eyepiece, fixed at either end of a tube 60.0 cm long. Assuming that this telescope would allow an observer to view a lunar crater in focus with a completely relaxed eye, what is ...
*April 22, 2010*

**Physics**

A standard 14.6-inch or .360 meter computer monitor is 1024 pixels wide and 768 pixels tall. Each pixel is a square approximately 281 micrometers on each side. If the maximum distance between the screen and your eyes at which you can just barely resolve two adjacent pixels is ...
*April 22, 2010*

**algebra**

A person is 3 times as old as aonther person but in 15 years she will only be 2 times as old. I found the answer the younger person is 15 years old and the older person is 45 years old. But 15 years from now the younger person will be 30 years old and the older person will be ...
*March 17, 2010*

**College Physics**

Two long, straight, parallel wires 8.0 cm apart carry currents in opposite directions. Use the right-hand source and force rules to determine whether the forces on the wires are attractive or repulsive. a)Repulsive b)Attractive If the wires carry equal currents of 4.0 A, what ...
*February 19, 2010*

**College Physics**

A solenoid is wound with 290 turns per centimeter. An outer layer of insulated wire with 200 turns per centimeter is wound over the solenoid's first layer of wire. When the solenoid is operating, the inner coil carries a current of 10 A and the outer coil carries a current...
*February 19, 2010*

**College Physics**

Two long, parallel wires separated by 50 cm each carry currents of 3.0 A in a horizontal direction. Find the magnetic field midway between the wires if the currents are in the same direction. B= T Find if they are in opposite directions. B= T
*February 19, 2010*

**College Physics**

A charged particle travels undeflected through perpendicular electric and magnetic fields whose magnitudes are 4000 N/C and 20 mT,respectively. Find the speed of the particle if it is a proton. v= m/s Find the speed of the particle if it is an alpha particle. (An alpha ...
*February 19, 2010*

**College physIcs**

An electron travels at a speed of 4.0×104 m/s through a uniform magnetic field whose magnitude is 1.4×10−3 T. What is the magnitude of the magnetic force on the electron if its velocity and the magnetic field are perpendicular? F= N What is the magnitude of ...
*February 19, 2010*

**College Physics**

Two 9.1 ohms resistors are connected in parallel, as are two 5.9 ohms resistors. These two combinations are then connected in series in a circuit with a 20 V battery. What is the current in each resistor? I9.1, I5.9 = A What is the voltage across each resistor? V9.1,V5.9 = V
*February 12, 2010*

**College Physic**

A galvanometer with a full-scale sensitivity of 500 microA and a coil resistance of 60 ohms is to be used to build an ammeter designed to read 7.5 A. What is the required shunt resistance? Rs = milliA
*February 12, 2010*

**College physcs**

Two 9.1 ohms resistors are connected in parallel, as are two 5.9 ohms resistors. These two combinations are then connected in series in a circuit with a 20 V battery. What is the current in each resistor? I9.1, I5.9 = A What is the voltage across each resistor? V9.1,V5.9 = V
*February 10, 2010*

**College physcs**

A galvanometer with a full-scale sensitivity of 500 microA and a coil resistance of 60 ohms is to be used to build an ammeter designed to read 7.5 A. What is the required shunt resistance? Rs = milliA
*February 10, 2010*

**College physcs**

A capacitor in a single-loop RC circuit is charged to 64% of its final voltage in 1.5 s. Find the time constant for the circuit. Find the percentage of the circuit's final voltage after 3.9 s . Vc/Vi= %
*February 10, 2010*

**College physcs**

Three resistors with values 1.1 , 3.4 , and 5.8 are connected in parallel in a circuit with a 6.4 battery. What is the total equivalent resistance? R = ohms
*February 10, 2010*

**College Physics**

A single resistor is wired to a battery. Define the total power dissipated by this circuit as P(initial). What is the Power? Now, a second identical resistor is wired in series with the first resistor. What is the power, in terms of P(initial), dissipated by this circuit? The ...
*February 8, 2010*

**College Physics**

In a proton linear accelerator, a 8.6 proton current hits a target. 5.4×10^16 protons/second hit the target. How much energy is delivered to the target each second if each proton has a kinetic energy of 26 MeV and loses all its energy in the target? U = J/s If the target...
*February 7, 2010*

**College Physics**

To move 5.0 C of charge from one electrode to the other, a 12-V battery must do how much work? 60 J 5.0 C 12 J 12 V 60 W
*February 6, 2010*

**College Physics**

Current passes through a solution of sodium chloride. In 1.00 second, 2.68 x 10^16 Na+ ions arrive at the negative electrode and 3.92 x 10^16 Cl-ions arrive at the positive electrode. What is the current passing between the electrodes? Current = mA What is the direction of the...
*February 6, 2010*

**College Physics**

Current passes through a solution of sodium chloride. In 1.00 second, 2.68 x 10^16 Na+ ions arrive at the negative electrode and 3.92 x 10^16 Cl-ions arrive at the positive electrode. What is the current passing between the electrodes? Current = mA What is the direction of the...
*February 6, 2010*

**College Physics**

A single resistor is wired to a battery.Define the total power dissipated by this circuit as P initial. What is the power, in terms of P initial, dissipated by this circuit? Power = P initial.
*February 6, 2010*

**College Physics**

If the voltage across an ohmic resistor is quadrupled, the power expended in the resistor increases by a factor of 4. decreases by a factor of 4. increases by a factor of 16. none of the preceding
*February 6, 2010*

**College Physics**

On average, an electric water heater operates for 3.4h each day. If the cost of electricity is $0.3 kWh, what is the cost of operating the heater during a 30-day month? The power of a typical electric water heater is 4500 W. Cost= Dollars What is the resistance of a typical ...
*February 6, 2010*

**College Physics**

Two copper wires have equal cross-sectional areas and lengths of 2.4m and 1.3m, respectively. What is the ratio of the current in the shorter wire to that in the longer one if they are connected to the same power supply? I1.3/I2.4 =
*February 6, 2010*

**College Physics**

A 1500-W heater is designed to be plugged into a 120-V outlet. What current will flow through the heating coil when the heater is plugged in? I = A What is R , the resistance of the heater? How long does it take to raise the temperature of the air in a good-sized living room 3...
*February 6, 2010*

**College Physics**

When switch S in the figure is open, the voltmeter V of the battery reads 3.13V . When the switch is closed, the voltmeter reading drops to 2.90V , and the ammeter A reads 1.70A. Assume that the two meters are ideal, so they do not affect the circuit. emf= V sorry I left out ...
*February 6, 2010*

**College Physics**

When switch S is open, the voltmeter V of the battery reads 3.13 . When the switch is closed, the voltmeter reading drops to 2.90 , and the ammeter A reads 1.70 . Assume that the two meters are ideal, so they do not affect the circuit. emf= V
*February 6, 2010*

**College Physics**

Current passes through a solution of sodium chloride. In 1.00 second,2.68 x 10^16 Na+ ions arrive at the negative electrode and 3.92 10^16 Cl- ions arrive at the positive electrode. What is the current passing between the electrodes? mA What is the direction of the current? ...
*February 6, 2010*

**College Physics**

Calculate the voltage required to accelerate a beam of protons initially at rest if they have a kinetic energy of 4.5keV. deltaV = V Calculate their speed if they have a kinetic energy of 4.5keV . v = m/s
*January 31, 2010*

**College Physics**

Calculate the voltage required to accelerate a beam of protons initially at rest if they have a kinetic energy of 2.7 eV. deltaV = V Calculate their speed if they have a kinetic energy of 2.7 eV . v = m/s
*January 31, 2010*

**College Physics**

A 12.0- A 12.0- A 12.0-V battery remains connected to a parallel plate capacitor with a plate area of 0.204m^2 and a plate separation of 3.14mm . What is the charge on the capacitor? Q = C How much energy is stored in the capacitor? Uc = J What is the electric field between ...
*January 31, 2010*

**physics**

How much work is required to completely separate two charges (each -1.9 microC ) and leave them at rest if they were initially 6.0mm apart?
*January 31, 2010*

**physics**

How much work is required to completely separate two charges (each -1.9 microC ) and leave them at rest if they were initially 6.0mm apart?
*January 31, 2010*

**College Physics**

The triangle is an equilateral triangle: 20 cm x 20 cm x 20 cm. What is the value of the electric potential at the center of the triangle if q1= 5.0 nicroC , q2= 5.0 microC, q3= -4.2 microC? V = 4.52 x 10^5V but I can not get this answer. What is the value of the electric ...
*January 31, 2010*

**Physics**

Two 0.09g pith balls are suspended from the same point by threads 40cm long. (Pith is a light insulating material once used to make helmets worn in tropical climates.) When the balls are given equal charges, they come to rest 19 cm apart What is the magnitude of the charge on ...
*January 25, 2010*

**Physics**

physics - drwls, Sunday, January 24, 2010 at 2:50am Compute the angle of the strings from vertical. It is sin^-1 (8.5/40) Call this angle A If the string tension is T T sin A = F (the Coulomb force) T cos A = M g tan A = F/Mg You need to say what the units of the mass are. All...
*January 25, 2010*

**physics**

Two 0.09 pith balls are suspended from the same point by threads 40 long. (Pith is a light insulating material once used to make helmets worn in tropical climates.) When the balls are given equal charges, they come to rest 19 cm apart What is the magnitude of the charge on ...
*January 23, 2010*

**physics**

Two 0.09 pith balls are suspended from the same point by threads 40 long. (Pith is a light insulating material once used to make helmets worn in tropical climates.) When the balls are given equal charges, they come to rest 19 apart. What is the magnitude of the charge on each ...
*January 23, 2010*

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