Wednesday

September 17, 2014

September 17, 2014

Total # Posts: 88

**Physics**

It's actually 7.643 N for (a) and 18.5 m/s^2 for centripetal acceleration in (b). Please help with the 2nd part!
*October 19, 2013*

**Physics**

One end of a cord is fixed and a small 0.270-kg object is attached to the other end, where it swings in a section of a vertical circle of radius 2.50 m, as shown in the figure below. When θ = 18.0°, the speed of the object is 6.80 m/s. (a) At this instant, find the ...
*October 19, 2013*

**General Chemistry**

The enthalpy of vaporization of benzene liquid is 33.9 kJ/mol at 298 K. How many liters of benzene gas, measured at 298 K and 95.1 mmHg, are formed when 1.54 kJ of heat is absorbed by benzene liquid at a constant temperature of 298 K? I think we use the ideal gas law, but I&#...
*September 19, 2013*

**Physics**

A ball is thrown upward from the ground with an initial speed of 23.2 m/s; at the same instant, another ball is dropped from a building 20 m high. After how long will the balls be at the same height?
*September 15, 2013*

**Physics**

A rocket is launched at an angle of 50.0° above the horizontal with an initial speed of 105 m/s. The rocket moves for 3.00 s along its initial line of motion with an acceleration of 32.0 m/s2. At this time, its engines fail and the rocket proceeds to move as a projectile...
*September 15, 2013*

**Physics**

A car is parked on a cliff overlooking the ocean on an incline that makes an angle of 20.0° below the horizontal. The negligent driver leaves the car in neutral, and the emergency brakes are defective. The car rolls from rest down the incline with a constant acceleration ...
*September 15, 2013*

**Physics**

From the window of a building, a ball is tossed from a height y0 above the ground with an initial velocity of 9.40 m/s and angle of 23.0° below the horizontal. It strikes the ground 6.00 s later. Initial velocity components: vx = 8.65 m/s vy = -3.67 m/s (c) Find the ...
*September 15, 2013*

**Physics**

A novice golfer on the green takes three strokes to sink the ball. The successive displacements of the ball are d1 = 3.96 m to the north, d2 = 2.06 m northeast, and d3 = 1.13 m at 30.0° west of south (see the figure). Starting at the same initial point, an expert golfer ...
*September 15, 2013*

**Physics**

A map suggests that Atlanta is 730 miles in a direction 5.00° north of east from Dallas. The same map shows that Chicago is 560 miles in a direction 21.0° west of north from Atlanta. The figure below shows the location of these three cities. Modeling the Earth as flat...
*September 15, 2013*

**Physics**

I set the two position equations together and got 0.86 s as my time. Thanks!
*September 14, 2013*

**Physics**

A ball is thrown upward from the ground with an initial speed of 23.2 m/s; at the same instant, another ball is dropped from a building 20 m high. After how long will the balls be at the same height?
*September 14, 2013*

**Physics**

A small mailbag is released from a helicopter that is descending steadily at 2.36 m/s. (a) After 5.00 s, what is the speed of the mailbag? (b) How far is it below the helicopter? (c) What are your answers to parts (a) and (b) if the helicopter is rising steadily at 2.36 m/s? I...
*September 12, 2013*

**Physics**

I got 192.6 meters as my max height, but I don't think that's right. We haven't learned KE and PE yet.
*September 11, 2013*

**Physics**

A model rocket is launched straight upward with an initial speed of 57.0 m/s. It accelerates with a constant upward acceleration of 1.50 m/s2 until its engines stop at an altitude of 190 m. (a) What is the maximum height reached by the rocket? (b) How long after liftoff does ...
*September 11, 2013*

**Physics**

I solved for time, did the quadratic & got 43.9 seconds. I used that to get a distance of 96.4 meters. The program said that they are both incorrect (might be due to significant figures) so I'm not sure where I went wrong.
*September 11, 2013*

**Physics**

A hockey player is standing on his skates on a frozen pond when an opposing player, moving with a uniform speed of 2.0 m/s, skates by with the puck. After 2.00 s, the first player makes up his mind to chase his opponent. If he accelerates uniformly at 0.10 m/s2, determine each...
*September 11, 2013*

**Physics**

A train is traveling down a straight track at 25 m/s when the engineer applies the brakes, resulting in an acceleration of −1.0 m/s2 as long as the train is in motion. How far does the train move during a 50 s time interval starting at the instant the brakes are applied?
*September 11, 2013*

**General Chemistry**

Calculate the pH and include the balanced equation for the acid dissociation reaction. 0.20 M HC3H5O2 (propionic acid, Ka = 1.3 x 10^-5)
*July 29, 2013*

**General Chemistry**

If HBR was added, would water form? HBr (aq) + NaOH (aq) -> H2O (l) + NaBr (aq)
*July 16, 2013*

**General Chemistry**

When a solution of nickel (II) chloride is mixed with a stoichiometric amount of colorless sodium hydroxide solution, a green, gelatinous precipitate forms. (a) Write the balanced molecular equation and the net-ionic equation for this reaction. molecular: Ni(Cl)2 (aq) + NaOH (...
*July 16, 2013*

**General Chemistry**

H2 (g) + I2 (g) -> 2HI (g) What would happen to the amount of iodide present if hydrogen iodide is added? Removed? The volumeof the system is decreased? I got increase, decrease & same as my answer, but I don't completely understand it. Please help.
*July 13, 2013*

**General Chemistry**

Write the competing equilibrium that will occur when a strong acid is added to the following equilibrium: Ca (aq) + C2O4 (aq) -> CaC2O4 (s)
*July 13, 2013*

**General Chemistry**

I don't really understand which is the mass of the sample.
*July 12, 2013*

**General Chemistry**

A 0.484 g sample of impure NH4Br is treated with 25.00 mL of 0.2050 M NaOH & heated to drive off the NH3. The unreacted NaOH in the reaction mixture after heating required 9.95 mL of 0.0525 M H2C2O4 to neutralize. How many grams of NH4Br were in the original sample? What is ...
*July 12, 2013*

**Chemistry**

A 0.355 g sample of a solid, monoprotic acid having a molar mass of 121 g/mol requires 18.47 mL NaOH for neutralization. Calculate the molarity of the NaOH solution. I got 0.159 M NaOH
*July 11, 2013*

**Physics**

Thank you. Your answer is correct, but I get a different answer when I try to calculate that last equation myself. I must be in kelvin or something.
*April 21, 2013*

**Physics**

A pot of water is boiling under one atmosphere of pressure. Assume that heat enters the pot only through its bottom, which is copper and rests on a heating element. In two minutes, the mass of water boiled away is m = 2.5 kg. The radius of the pot bottom is R = 8.5 cm and the ...
*April 21, 2013*

**Physics**

A closed box is filled with dry ice at a temperature of -81.5 C, while the outside temperature is 27.4 C. The box is cubical, measuring 0.307 m on a side, and the thickness of the walls is 4.47 × 10-2 m. In one day, 3.37 × 106 J of heat is conducted through the six...
*April 21, 2013*

**Physics**

With the ladder laying flat on the ground, the axis is on the left and it is being pulled upward on the right. But the center of gravity confuses me. I don't know how that comes into play. These topics are still new to me.
*March 17, 2013*

**Physics**

A 8.78 -m ladder with a mass of 23.8 kg lies flat on the ground. A painter grabs the top end of the ladder and pulls straight upward with a force of 236 N. At the instant the top of the ladder leaves the ground, the ladder experiences an angular acceleration of 1.90 rad/s2 ...
*March 17, 2013*

**Language**

Thank you:)!!!
*March 1, 2012*

**Language**

The book says:" Add as many prefixes as u can to the word "form". Try to make at least 5 words.
*March 1, 2012*

**Language**

Thank you:))!!!!
*March 1, 2012*

**Language**

What is the longer form for this clipped word" caf "?Thank u
*March 1, 2012*

**Language**

Thank you for helping me:)
*January 20, 2012*

**Language**

Thanks !!!!
*January 20, 2012*

**Language**

Homophones can be used humorously in riddles.The answer to each of the riddles below is a homophone groaner! a) What type of sandals do frogs like?Open_____. b)What is called when your rabbit is depressed? A bad_______day. c) What is the most important part of a horse? The ...
*January 20, 2012*

**Economics**

Slim city is a town resided by slim people, with no health club in town. LA Fatness has estimated that the annual demand for their Fatness Club in this town to be Q = 160 - P. Every Club member has a marginal cost of $40, and the annual fixed cost of the business is $500 (...
*April 19, 2011*

**character traits**

thanks!
*December 5, 2010*

**character traits**

please name some character traits for a boy that believes in his pups, and waits to see what they do. He also is a little pushy.
*December 5, 2010*

**math**

(e^(e^x)) = 2 find x.
*August 14, 2010*

**Calculus**

Evaluate the limit using L'Hospital's rule if necessary. lim as x goes to +infinity x^(6/x)
*February 19, 2010*

**Calculus**

Evaluate the indefinite integral. (e^7x)/(e^14x+16)dx
*February 19, 2010*

**Calculus**

The half-life of Palladium-100 is 4 days. After 12 days a sample of Palladium-100 has been reduced to a mass of 4 mg. What was the initial mass (in mg) of the sample? What is the mass 5 weeks after the start?
*February 18, 2010*

**Calculus**

Evaluate the definite integral. xe^(–x^2)dx from 0 to 6
*February 11, 2010*

**Calculus**

From 2 to 3, integrate ((x^3)+5)dx/x.
*February 5, 2010*

**Calculus**

Let f(x) = ln(((2x–5) / (7x+4))^(1/2)). f'(x) = ...
*February 5, 2010*

**Calculus**

That's what I got too, but it says that it's wrong.
*February 4, 2010*

**Calculus**

Evaluate the indefinite integral. (5dx)/(xln(2x))
*February 4, 2010*

**Calculus**

Let f(x) = ln(((2x–5) / (7x+4))^(1/2)). f'(x) = ... I keep on getting the wrong answer.
*February 4, 2010*

**Calculus**

Let f(x) = 3(x^6)lnx. f'(x)= ...
*February 4, 2010*

**Calculus**

f-1(-3) = (5-7(-3))/((-3)-1) = 26/-4 = -13/2 thanks!
*February 4, 2010*

**Calculus**

Let f(x)=(x+7)/(x+5). inverse f-1(-3)=...
*February 4, 2010*

**Chemistry**

I got the answer.
*January 29, 2010*

**Chemistry**

Monosodium glutamate (MSG), a food-flavor enhancer, has been blamed for “Chinese Restaurant Syndrome,” the symptoms of which are headaches & chest pains. MSG has the following composition by mass: 35.51 percent C, 4.77 percent H, 37.85 percent O, 8.29 percent N, & 13...
*January 29, 2010*

**Calculus**

(38.7-32)/2=3.35 It's not the correct answer.
*January 28, 2010*

**Calculus**

A car drives down a road in such a way that its velocity (in m/s) at time t (seconds) is v(t)=3(t^(1/2))+4. Find the car's average velocity (in m/s) between t=4 and t=6.
*January 28, 2010*

**Calculus**

A car drives down a road in such a way that its velocity ( in m/s) at time t (seconds) is v(t)=3(t^(1/2))+4. Find the car's average velocity (in m/s) between t=4 and t=6.
*January 27, 2010*

**Calculus**

Yeah. Thanks. I found out that the limits are from 0 to 2 and 2 to 3.
*January 27, 2010*

**Calculus**

The total area enclosed by the graphs of y=6(x^2)–(x^3)+x and y=(x^2)+7x is ..
*January 27, 2010*

**Calculus**

I got that the first time, but I though something was wrong.
*January 27, 2010*

**Calculus**

Find the average value of the function on the given interval: f(x)=cos(16x), [0,pi/2] The answer I got is 1.
*January 27, 2010*

**chemistry**

Hey how did you find the stand cell volutage of MnCl2 and KMNO4?
*December 2, 2009*

**algebra (check plz)**

okay (: thanks again for your help!
*October 26, 2009*

**algebra (check plz)**

thanks!! (((: what about D.? ):
*October 26, 2009*

**algebra (check plz)**

write an equation in slope-intercept form of the line that passes through the given points. a. (-6,1), (3,-7) b. (-2/3,4), (6, -1/3) write an equation in point-slope form of the line that passes through the given poitns. c. (-2,5), (4,-3) d. (1/2,-1), (-2/3,6) ...
*October 26, 2009*

**algebra (check?plz)**

a. y = -8x/3 + 1 b. y = -13x/20 + 107/30 c. y + 3 = (-4/3)(x + 2) d. y + 1 = -6x + 3 are these correct?
*October 26, 2009*

**algebra**

write an equation in slope-intercept form of the line that passes through the given points. a. (-6,1), (3,-7) b. (-2/3,4), (6, -1/3) write an equation in point-slope form of the line that passes through the given poitns. c. (-2,5), (4,-3) d. (1/2,-1), (-2/3,6) plz show me how ...
*October 26, 2009*

**maths**

write an equation of the line that is parallel to the given line and passes through the given point. y=-4x-7, (5,-3) y=-2/3x+4, (-5,5)
*October 25, 2009*

**[math]**

How do I solve this equation algebraically? 1/2x + 2/3 = 1/8x - 3/2 Thank you.
*October 7, 2009*

**Math!**

Use the Midpoint Rule to approximate the integral from 2 to 7 S(–3x–7x^2)dx with n=3.
*June 8, 2009*

**Math!**

Consider the integral from 3 to 6 S(2x^2+4x+3)dx (a) Find the Riemann sum for this integral using right endpoints and n=3. (b) Find the Riemann sum for this same integral, using left endpoints and n=3.
*June 8, 2009*

**Math!**

I see it now.
*June 4, 2009*

**Math!**

A spherical snowball is melting in such a way that its diameter is decreasing at rate of 0.4 cm/min. At what rate is the volume of the snowball decreasing when the diameter is 10 cm. (Note the answer is a positive number).
*June 4, 2009*

**Math!**

Yeah. That's better. Thanks again!
*June 4, 2009*

**Math!**

This answer isn't right either & I don't understand how you got d^2 = 221.847.
*June 4, 2009*

**Math!**

At noon, ship A is 50 nautical miles due west of ship B. Ship A is sailing west at 25 knots and ship B is sailing north at 16 knots. How fast (in knots) is the distance between the ships changing at 6 PM? (Note: 1 knot is a speed of 1 nautical mile per hour.)
*June 4, 2009*

**Math (:**

The answer is -3.9300. Thanks!
*June 4, 2009*

**Math (:**

I use an online homework program called WebWork. It just tells you if your answer is correct or not.
*June 4, 2009*

**Math (:**

I copied & pasted this from my online homework. It said the answer is wrong.
*June 4, 2009*

**Math (:**

My answer is -3.9319, but it's wrong.
*June 4, 2009*

**Math (:**

The altitude of a triangle is increasing at a rate of 2.500 centimeters/minute while the area of the triangle is increasing at a rate of 1.500 square centimeters/minute. At what rate is the base of the triangle changing when the altitude is 10.500 centimeters and the area is ...
*June 4, 2009*

**Math (:**

My answer was around the thousands. That's how I knew it was wrong. Thanks!
*June 4, 2009*

**Math (:**

No. Sorry :[
*June 4, 2009*

**Math (:**

My answer doesn't make sense. It's too big. A Norman window has the shape of a semicircle atop a rectangle so that the diameter of the semicircle is equal to the width of the rectangle. What is the area of the largest possible Norman window with a perimeter of 47 feet?
*June 4, 2009*

**science**

describe what happens when a nucleus is stabilized by emitting positrons
*December 10, 2008*

**Ethics**

What is the familial convention for Puerto Ricans?
*March 2, 2008*

**acids and alkalis**

Btw, UI starts clear - it is green at neutral :)
*November 4, 2006*

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