Thursday

November 27, 2014

November 27, 2014

Total # Posts: 2,120

**Thermodynamics**

Drawing a blank studying last minute for an exam: when does a piston cylinder not follow the 2nd law of thermodynamics!!!!
*November 25, 2014*

**pt1420 **

if the expression is false, the_____ operator will return true.
*November 24, 2014*

**Chemistry 211**

Which of the following statements is a reasonable explanation for why a percent yield may be less than 100% for the synthesis of the alum, select all that apply. a) The aluminium foil did not completely react b) Some alum sample remained in the beaker and was not transferred ...
*November 24, 2014*

**Physics**

A lathe, initially at rest, accelerates at .60 rad/s^2 for 10s, then runs at a constant angular velocity for 20s, and finally decelerates uniformly for 10s to come to a complete stop. What is its average angular velocity?
*November 23, 2014*

**Physics**

A boy wants to throw a ball into his friend’s window 16.0 m above. Assuming it just reaches the window, he throws the ball at 55.0° to the ground. At what velocity should he throw the ball?
*November 23, 2014*

**Physics**

A lathe, initially at rest, accelerates at .60 rad/s^2 for 10s, then runs at a constant angular velocity for 20s, and finally decelerates uniformly for 10s to come to a complete stop. What is its average angular velocity?
*November 23, 2014*

**4th grade Math**

What is an expression that can be used to find 4 x 275 using mental math and properties of numbers?
*November 18, 2014*

**Physics**

The pistons of a hydraulic press have radii of 2.00cm and 12.00cm, respectively. A) What force must be applied to the smaller piston to exert a force of 5250N on the larger piston? B) What is the pressure in (N/cm2) on each piston? C) What is the mechanical advantage of the ...
*November 16, 2014*

**Calculus**

I got this equation from some girl that is on an online dating service. She says she wants to date someone who knows what those numbers mean, and she's hot....I'll give you the web info if you want it, just for fun of course.
*November 10, 2014*

**Calculus**

What does this equation mean? X = Cos (T) * Phi ^ ((2 / Pi) * T) Y = Sin (T) * P
*November 10, 2014*

**Physics**

A space vehicle is orbiting Earth in a circular orbit with a radius of 10,300,000m. What is the minimum increase in speed that is needed for the vehicle to escape Earth's gravitational field? The mass of the Earth is 5.97x10^24 kg and G = 6.67x10^-11 N*m^2/kg^2. The answer...
*November 10, 2014*

**Physics**

A mass of 100g is attached to one end of a massless rod, 10cm in length, which is pivoted about the opposite end. The rod is held vertical, with the mass at the top, and released. The rod swings. A. What is the speed of the mass at the instant that the rod is horizontal? B. ...
*November 10, 2014*

**Math**

What is the probability that a randomly thrown dart hits a shaded region, given that the dart lands within the rectangle? All of the circles are congruent, and the diameter of each circle is 6 cm.
*November 6, 2014*

**Physics**

An object of mass 1.00 kg is attached to a vertical spring with spring constant 100 N/m. The object is held at rest in a position such that the spring is stretched upward a distance 1.00 cm beyond its undisturbed length. If the object is released, how far will it drop before ...
*November 5, 2014*

**algebra**

In a change jar, Tom has nickels and dimes. The number of nickels is two times the number of dimes and the total amount of money in the jar is $1.20. How many dimes are in the jar?
*November 4, 2014*

**chemistry**

50 mL of water at 48.9EC were mixed with 50 mL of water at 23.8EC in a calorimeter also at 23.8EC. The final temperature was 33.1EC. Assuming that neither the density of water nor its specific heat capacity change with temperature, calculate the total heat capacity of the ...
*November 3, 2014*

**physics**

A ball is rolled up a ramp at 2.50 m/s. The ball slows down for 5.00 s and then rolls back down. Assume frictions isn't a factor and that the up ramp is the positive. At what point does the ball's acceleration change and what is the acceleration on the way down?
*October 30, 2014*

**Math**

Use the distributive property to rewrite the expression 1/2(C-8)=
*October 27, 2014*

**Math**

Find a fraction between 7/9 & 8/9
*October 23, 2014*

**Math**

Please check 2/5 + (-7/8) = -6
*October 15, 2014*

**Math **

Please check 15/16 x 2/3 = 5/8
*October 15, 2014*

**Linear Algebra**

Find the eigenvalues and corresponding eigenvectors of the matrix: 0 0 1 M = 1 0 0 0 1 0
*October 13, 2014*

**Math**

If I plan to average 80 kilometers per hour and stop 45 minutes for lunch how long will it take me to make a 220 kilometer trip?
*October 9, 2014*

**Math**

(5.63+.918) - (.83+.9) = 6.548 - .173 = 6.375
*October 9, 2014*

**Math**

How do rate tables help me find equivalent ratios
*October 9, 2014*

**Chemistry**

The oxidation of iodide ion by arsenic acid, H3AsO4, is described by the balanced equation 3I−(aq)+H3AsO4(aq)+2H+(aq)→ I3−(aq)+H3AsO3(aq)+H2O(l) If −Δ[I−]/Δt = 4.8×10−4M/s , what is the value of Δ[I3−]/Δt ...
*October 5, 2014*

**Chemistry**

The oxidation of iodide ion by arsenic acid, H3AsO4, is described by the balanced equation 3I−(aq)+H3AsO4(aq)+2H+(aq)→ I3−(aq)+H3AsO3(aq)+H2O(l) If −Δ[I−]/Δt = 4.8×10−4M/s , what is the value of Δ[I3−]/Δt ...
*October 5, 2014*

**statistics**

In a major city 7 % of cars have an alarm system installed. A car without an alarm has a probability of 0.01 of being stolen, this is triple the probability of a car with an alarm being stolen. What is the probability that a car stolen from this city has an alarm system ...
*October 4, 2014*

**math **

Michael's father broughthim a 16-foot board to cut into 11 equal sizes lengths for his shelves The saw blade that Michael will use to cut the board will change the length of the board by -0.125 inches for each cut. How will this affect the total length of the board?
*October 3, 2014*

**Physics**

6.5 ft
*September 21, 2014*

**math**

5 1/2
*September 21, 2014*

**Math**

Place parentheses to make this statement true: 6-6/6x6+6=0
*September 21, 2014*

**Chemistry**

wow thats really easy, thank you
*September 21, 2014*

**Chemistry**

What osmotic pressure in atmospheres would you expect for a solution of 0.150M CaCl2 that is separated from pure water by a semipermeable membrane at 310 K? Assume 100% dissociation for CaCl2 Any help is appreciated, thank you!
*September 21, 2014*

**Chemistry**

Thanks, I figured this one out, can you help me on the other one?
*September 21, 2014*

**Chemistry**

What partial pressure of oxygen above the water (in atmospheres at 0 C ) is needed to obtain this concentration? The solubility of O2 in water at 0 C and 1 atm partial pressure is . 2.21 x 10^-3 mol/L Concentration needed is 4mg/L Stuck and need help, anything is appreciated!
*September 21, 2014*

**chemistry**

What is the density of a piece of zinc that has a volume of 8000 cubic cm? density= mass/ volume
*September 21, 2014*

**Chemistry**

If the edge length of an NaH unit cell is 488pm, what is the length (in picometers) of an Na−H bond? Na−H has face-centered cubic unit cell. Please help
*September 14, 2014*

**Chemistry**

An element crystallizes in a body-centered cubic lattice. The edge of the unit cell is 3.13Å , and the density of the crystal is 7.78g/cm3. Calculate the atomic weight of the element. Please help, thanks
*September 14, 2014*

**physics**

A certain circuit breaker trips when the rms current is 50.0 A. What is the corresponding peak current?
*September 13, 2014*

**physics**

A North American tourist takes his 22.0–W, 120–V AC razor to Europe, finds a special adapter, and plugs it into 240 V AC. Assuming constant resistance, what power does the razor consume as it is ruined?
*September 13, 2014*

**physics**

P = I²R = 1*2.5 = 2.5 watts 1 watt is a Joule per second, or a Joule is a watt-second E = 2.5 J/s x 4.0s = 10 Joules It says I need more numbers for the answer...
*September 13, 2014*

**physics**

A current of 1 A is maintained in a simple circuit with a total resistance of 2.5 Ω. How much heat is generated in 4.0 s?
*September 13, 2014*

**physics**

A light–rail commuter train draws 645 A of 590–V DC electricity when accelerating. What is its power consumption rate in kilowatts? How long does it take to reach 30.0 m/s starting from rest if its loaded mass is 4.50×104 kg, assuming 91.0% efficiency and ...
*September 13, 2014*

**physics**

I got the first part of the question right. It was 32.2 W How would I do the second part?
*September 13, 2014*

**physics**

A cauterizer, used to stop bleeding in surgery, puts out 2.30 mA at 14.0 kV. What is its power output? What is the resistance of the path?
*September 13, 2014*

**Physics**

With a 1220–W toaster, how much electrical energy is needed to make a slice of toast (cooking time = 1.3 minute)? At 12.1 cents/kW·h, how much does this cost? (You do not need to enter any units.)
*September 13, 2014*

**10**

A runner is at the starting gate and hears the starting gun. He begins running with a constant acceleration ai = 0.55 m/s2. He crosses the finish line at d = 100 m and then begins slowing down. It takes him tr to cross the finish line. It takes him ts = 6.5 s to return to rest...
*September 11, 2014*

**10**

A runner is at the starting gate and hears the starting gun. He begins running with a constant acceleration ai = 0.55 m/s2. He crosses the finish line at d = 100 m and then begins slowing down. It takes him tr to cross the finish line. It takes him ts = 6.5 s to return to rest...
*September 11, 2014*

**6**

A student begins at rest and then walks north with an average speed of v1 = 0.85 m/s. The student then turns south and walks with an average speed v2 = 0.45 m/s. (a) What was the student's overall average velocity vavg, x, in m/s, for the trip assuming the student spent ...
*September 11, 2014*

**3**

t= 5.79 (a) There are approximately 1609 meters per mile. If the sun is 93 million miles away, how far is the sun in kilometers to two significant figures.
*September 11, 2014*

**3**

An astronomy student is studying the sun. While monitoring her equipment, she observes a solar flare. She then observes the reflection of the solar flare off of a passing satellite and with her equipment she is able to determine that the reflected light arrives from the ...
*September 11, 2014*

**2**

Assume that an intercontinental ballistic missile goes from rest to a suborbital speed of 6.50 km/s in 60.0 s (the actual speed and time are classified). What is its average acceleration in m/s2 and in multiples of g (9.80 m/s2)?
*September 11, 2014*

**2**

A student witnesses a flash of lightning and then t = 6.5 s later the student hears the associated clap of thunder. Light travels at 3.0 × 108 m/s in the air. How long, t1, in seconds did it take the light to reach the student's eyes after the flash?
*September 11, 2014*

**1**

A student witnesses a flash of lightning and then t = 6.5 s later the student hears the associated clap of thunder. Light travels at 3.0 × 108 m/s in the air. How long, t1, in seconds did it take the light to reach the student's eyes after the flash?
*September 11, 2014*

**1**

A student witnesses a flash of lightning and then t = 6.5 s later the student hears the associated clap of thunder. Sound travels at 343 m/s in the air. What distance from the student is the lightning strike, in meters?
*September 11, 2014*

**physics**

Assume that an intercontinental ballistic missile goes from rest to a suborbital speed of 6.50 km/s in 60.0 s (the actual speed and time are classified). What is its average acceleration in m/s2 and in multiples of g (9.80 m/s2 )?
*September 11, 2014*

**physics**

A commuter backs her car out of her garage with an acceleration of 1.40 m/s2. (a) How long does it take her to reach a speed of 2.00 m/s? (b) If she then brakes to a stop in 0.800 s, what is her deceleration?
*September 11, 2014*

**Chemistry**

NaHCO3 + HCl = NaCl + H2O + CO2 The there are .0489 moles of CO2, and HCL is 6M. find the amount of HCL in mL and the grams of NaHCO3
*September 7, 2014*

**physics**

Clint Dempsey takes a free kick and kicks a soccer ball with a mass of 440 grams at 98 miles per hour. what is the momentum
*September 7, 2014*

**Physics-Electricity**

Consider three charged particles placed along the x-axis. The particle with q1 = 9.30 nC is at x = 6.87 m and q2 = 4.09 nC is at x = 0.600 m. Where must a positive charge, q3, be placed such that the resultant force on it is zero? x=?m
*August 31, 2014*

**physics**

Vector has a magnitude of 136 units and points 35.0 ° north of west. Vector points 69.0 ° east of north. Vector points 19.0 ° west of south. These three vectors add to give a resultant vector that is zero. Using components, find the magnitudes of (a) vector and (b...
*August 26, 2014*

**Physics**

wo objects each have a positive charge. The total charge on both objects is 365 µC. When the objects are placed a distance of 1.30 m apart, each exerts an electrostatic force of 24.3 N on the other. What is the charge on each object? (Give your answers in µC.)
*August 25, 2014*

**physics**

Find the ratio of the electrostatic to gravitational force between two electrons. 4.16×1042 What is this ratio for two protons? (Why is the ratio different for electrons and protons?)
*August 22, 2014*

**Physics**

If two equal charges each of 1.0 C each are separated in air by a distance of 1.0 km, what is the magnitude of the force acting between them? You will see that even at a distance as large as 1.0 km, the repulsive force is substantial because 1.0 C is a very significant amount ...
*August 22, 2014*

**Physics**

The figure below shows an electron passing between two charged metal plates that create an 115 N/C vertical electric field perpendicular to the electron’s original horizontal velocity. (These can be used to change the electron’s direction, such as in an oscilloscope...
*August 22, 2014*

**math**

If each edge of a cube is increased by 2 inches, the A. volume is increased by 8 cubic inches B. area of each face is increased by 4 square inches D. sum of the edges is increased by 24 inches
*August 14, 2014*

**Maths**

A ladder is inclined at an angle of 65degrees to the horizontal If the base of the ladder is 15.5m horizontally from the vertical wall What is the length of the ladder
*August 11, 2014*

**Chemistry**

A solution of calcium nitrate, Ca(NO3)2, reacts with a solution of ammonium fluoride, NH4F, to form solid calcium fluoride, CaF2, and ammonium nitrate, NH4NO3(aq). When 45.00 mL of 4.8724 x 10-1 M Ca(NO3)2 solution was added to 60.00 mL of 9.9981 x 10-1 M NH4F solution, 1.524 ...
*June 30, 2014*

**Chemistry**

A solution of calcium nitrate, Ca(NO3)2, reacts with a solution of ammonium fluoride, NH4F, to form solid calcium fluoride, CaF2, and ammonium nitrate, NH4NO3(aq). When 45.00 mL of 4.8724 x 10-1 M Ca(NO3)2 solution was added to 60.00 mL of 9.9981 x 10-1 M NH4F solution, 1.524 ...
*June 30, 2014*

**Chemistry**

A solution of calcium nitrate, Ca(NO3)2, reacts with a solution of ammonium fluoride, NH4F, to form solid calcium fluoride, CaF2, and ammonium nitrate, NH4NO3(aq). When 45.00 mL of 4.8724 x 10-1 M Ca(NO3)2 solution was added to 60.00 mL of 9.9981 x 10-1 M NH4F solution, 1.524 ...
*June 30, 2014*

**Chemistry**

A solution of calcium nitrate, Ca(NO3)2, reacts with a solution of ammonium fluoride, NH4F, to form solid calcium fluoride, CaF2, and ammonium nitrate, NH4NO3(aq). When 45.00 mL of 4.8724 x 10-1 M Ca(NO3)2 solution was added to 60.00 mL of 9.9981 x 10-1 M NH4F solution, 1.524 ...
*June 30, 2014*

**mathematics **

Evaluate the following integral 1. (^3 - 4x^2 -15x + 15) / (^2 - 2x -8) 2. X^3 / cube root (x^2 + 4)dx
*June 27, 2014*

**buisness math**

the single equivalent discount rate of the trade discount 3/3/1 is
*June 12, 2014*

**science-chemistry **

Calculate the number of moles of solute present in 450. g of an aqueous NaCl solution that is 0.565 % NaCl by weight
*June 12, 2014*

**us hist**

All of the following are reasons for Communist Russia's animosity toward the United States and the western powers except one. Which is the exception? a. Russia was not allowed to participate at the Treaty of Versailles. b. Russia felt the U.S. delayed the 2nd front in WWII...
*June 10, 2014*

**us hist**

A tactic that the United States used that was very successful against the Japanese in the Pacific Theater of War was called "Island Hopping." True/False Is true?
*June 9, 2014*

**Physics**

A golf ball is struck by a golf club at 55 m/s at an angle of 28.0o above the horizontal. The mass of the ball is 45 grams and is in contact with the golf club for 1.5 m/s. Calculate the average force exerted on the ball by the club.
*May 26, 2014*

**math question**

Begin by subtracting 1 from each side. x/4 = -7 then multiply both sides by 4 to get x = -28
*May 25, 2014*

**math**

Replace the m's with 2/5 and the n's with 1/2 2 multiplied times 2/5 + 1/2 2/1 times 2/5 = 4/5 4/5 + 1/2 you need a common denominator of 10 to finish the problem 8/10 + 5/10 = 13/10 or 1 3/10 Do the same thing for #2, but you will be subtracting 5/10 from 8/10
*May 25, 2014*

**ALGEBRA**

I am not sure what you are doing... but if your first value is x=3 then 7(3) -2y = -21 21 -2y = -21 -2y = -42 y = 2 Do the same thing for 0, but replace your y with the "0"
*May 25, 2014*

**Stats**

Thanks!! That really helped. I had the steps you had, but was stuck on z vs t.
*May 21, 2014*

**Stats**

I am working on a review sheet and got everything except for this one. I am not sure whether to use z or t. The number of hours per week that high school juniors watch TV is normally distributed with a mean of 8 hours and a standard deviation of 2 hours. If 100 students are ...
*May 21, 2014*

**math**

1 cm/ 50 m = 4 cm/? 4 is 4 times greater that 1 so you need 4 times greater than 50 = 200m Or use proportions and cross multiply 1(?) = 50(4) so ? = 200 m
*May 21, 2014*

**statistics**

An IQ is designed so that the mean is 100 and the standard deviation is 23 for the population of Normal adults, find the sample size necessary to estimate the mean IQ score of statistics students Such that it can be said with 90% confidence that the sample mean is within 5 IQ ...
*May 19, 2014*

**physics**

A girl throws a water-filled balloon at an angle of 50.0∘^\circ above the horizontal with a speed of 12.0m/s{\rm m}/{\rm s} . The horizontal component of the balloon's velocity is directed toward a car that is approaching the girl at a constant speed of 8.00m/s{\rm m...
*May 17, 2014*

**physics**

A girl throws a water-filled balloon at an angle of 50.0∘^\circ above the horizontal with a speed of 12.0m/s{\rm m}/{\rm s} . The horizontal component of the balloon's velocity is directed toward a car that is approaching the girl at a constant speed of 8.00m/s{\rm m...
*May 17, 2014*

**physics**

A girl throws a water-filled balloon at an angle of 50.0∘^\circ above the horizontal with a speed of 12.0m/s{\rm m}/{\rm s} . The horizontal component of the balloon's velocity is directed toward a car that is approaching the girl at a constant speed of 8.00m/s{\rm m...
*May 17, 2014*

**physics**

A physics book slides off a horizontal tabletop with a speed of 1.10m/s{\rm m}/{\rm s} . It strikes the floor in 0.350s{\rm s} . Ignore air resistance.
*May 17, 2014*

**Algebra 1**

You got the correct answer. Please explain every step in calculating this? What was the step by step procedure?
*May 15, 2014*

**Algebra 1**

For the 2 functions, f(x) and g(x), tables of values are shown below. What is the value of g(f(3))? x f(x) x g(x) ------- --------- -5 7 -2 3 -2 -5 1 -1 1 3 2 -3 3 2 3 -5
*May 15, 2014*

**Trig 3**

Sorry. Don't think I have those keys on this standard keyboard? I could be wrong. Let me ask. From step 2 to 3 ... we go from sin / cos squared separately to (sin/cos)2 or times 2 for each? That means the same thing in this case? We can't just go from step 2 to the ...
*May 15, 2014*

**Trig 3**

Why does 1 - COS2(Squared) _________________ COS2 = tan2
*May 15, 2014*

**Trig 2**

Steve, let's take this up a notch. My number is 800 828 2950 I'll send you my email? You are in the U.S. i take it? I'm here in Lorain county OH. i can send you a joinme link then you can see inside my pc while we talk on the phone together ...? We can do some ...
*May 13, 2014*

**Trig 2**

I just meant a 4 quad graph ...x and y intersecting like you have in the link. OK, this part is a trig rule? sin(2x) is always between -1 and 1. Because it covers 2 integers? One on either side of 0 (origin?)On the x axis? In this equation, they show no graph. If that matters...
*May 13, 2014*

**Trig 2**

What graph ...? Ok, so the quadratic 4 quadrant graph...? i appreciate the help but I can't see it ...
*May 13, 2014*

**Trig 2**

What is the smallest value for x where y = sin 2x reaches its maximum ...wtf that means.
*May 13, 2014*

**Trig**

Dude, throw me a bone ....? I'm try'n to learn. I see that A sin 60 degrees is equal to BC/8 (8 = the hypotenuse). C is a right angle. BC is the height. Wait. I think I see it now....? Because Sin equals BC(opposite)/H(8)and we know that the result of this equals .866...
*May 13, 2014*

**Trig**

Dude, throw me a bone ....? I'm try'n to learn. I see that A sin 60 degrees is equal to BC/8 (8 = the hypotenuse). C is a right angle. BC is the height. Wait. I think I see it now....? Because Sin equals BC(opposite)/H(8)and we know that the result of this equals .866...
*May 13, 2014*

**Trig**

If it helps the answer according to this ACT compass sample test questions print out is 6.93. How to solve it is the question ... C is a 90 degree angle. AB is 8 and the hypotenuse. AC is the base .... we don't know it's length. It's on page 14 if you google this...
*May 13, 2014*

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