Thursday

September 18, 2014

September 18, 2014

Total # Posts: 890

**physics**

A sprinter starts from rest and accelerates for 5s. He then travels at a constant velocity for 10s. Finally he slows down to a stop in 5s. Draw a distance time graph to represent his motion.
*September 17, 2014*

**Physics please help**

So i just find the slope of the curve
*September 16, 2014*

**Physics please help**

How do I convert a distance time graph into a velocity time graph. I am given a distance time graph with three curves but i am not sure how to calcualte the area of them to get the velocity time graph.
*September 16, 2014*

**Physics**

Heather and Jerry are standing on a bridge 43m above a river. Heather throws a rock straight down with a speed of 12m/s . Jerry, at exactly the same instant of time, throws a rock straight up with the same speed. Ignore air resistance.
*September 11, 2014*

**English**

In wuthering heights, what are the most influential forces in the shaping of a childs values and behaviour? Parents, guardians, or other family members?schooling? Friends? I think the answer would be parents, guardians or other family members
*September 9, 2014*

**Biology please help!**

Is respiratory control more sensitive to small changes in arterial PO2 or in arterial PCO2
*September 8, 2014*

**English**

What role, according to Dessner, does irony play in the story A&P by John Updikes? What levels of irony are at work in the story? For example, what does he identify as " charming irony" as compare to " deeper irony"? Explain
*August 30, 2014*

**Chemistry**

Using Hess’s Law with the following data: N2(g) + O2(g) = 2NO(g) Del(H) = 180.7kj 2NO(g) + O2(g) = 2NO2(g) Del(H)= -113.1kj 2N2O(g) = 2N2(g)+ O2(g) Del(H)=-163.2kj Calculate Del(H) for the reaction: N2O(g) + NO2(g) = 3NO(g)
*July 29, 2014*

**Chemistry**

Calculate the value of the standard enthalpy change for each of the following reactions (standard enthalpy for Na2SO4(s) is -1375.653 kj/mole): a)4HBr(g) + O2(g) = 2H2O(I) + 2Br(I) b)2Na(OH)(s) + SO3(g) = Na2SO4(s) + H2O(g) c)CH4(g) + 4CI2(g) = CCI4(I) + 4HCI(g) d)Fe2O3(s) + ...
*July 3, 2014*

**Chemistry**

Using standard enthalpies information, calculate the standard enthalpy change for this reaction. a)(thermite reaction) 2Al(s) + Fe2O3(s) = Al2O3(s) + 2Fe(s) b)Mg(OH)2(s) = MgO(s) + H2O(I) c)N2O4(g) + 4H2(g) = N2(g) + 4H2O(g) d)SiCl4(I) + 2H2O(I) = SiO2(s) + 4HCI(g)
*July 3, 2014*

**Chemistry**

Given the Data: N2(g) + O2g) = 2NO(g) delta H = 180.7kj, 2NO(g) + O2(g) = 2NO2(g) delta H = 0113.1kj, 2N2O(g) = 1N2(g) + O2(g) delta H = -163.2kj. Using Hess’s Law calculate delta H for the reaction: N2O(g) + NO2(g) = 3NO(g)
*July 3, 2014*

**Chemistry**

A solution of hydrogen peroxide, H2O2, is titrated with potassium permanganate, KMnO4, according to the following equation: 5H2O2 + 2KMnO4 + 3H2SO4 = 5O2 + 2MnSO4 + 8H2O + K2SO4. It requires 46.0 mL of 0.145 Mol/L KMnO4 to titrate 50.0 mL of the solution of H2O2. What is the ...
*July 3, 2014*

**music**

I think your ideas are great,but you need to decide together. Why don't you talk to them and negotiate the correct song to fit with you. Find a time at school, after school, at a dance studio or all of them. It is great to practice and practice does make perfection. If ...
*June 7, 2014*

**Math**

Please help, I don't understand.
*May 23, 2014*

**Math**

What is the degree of the monomial? 6x^5
*May 23, 2014*

**Physics**

1.How are alternating and direct current different? 2.Who invented direct current? 3.Who invented alternating current? 4.What are some of the advantages of alternating current? 5.Do all devices that plug into the wall run on alternating current? Why/why not? 6.What is the ...
*May 20, 2014*

**chemistry**

20 mL of 0.125 M potassium iodide solution is mixed with 10 mL of 0.1 g L–1 sodium thiosulfate solution and 0.2 g of solid iodine indicator is added. To this solution is added 20 mL of 0.025 M peroxodisulfate solution. After 46 seconds a blue colour appears, indicating ...
*May 9, 2014*

**PHYSICS HELP**

A long, ideal solenoid has a diameter d=12cm and n=1200turns/meter carrying current I=20A. If the current is lowered at 4.33amp/s to zero, what is the magnitude of the induced electric field in V/m at a position 8.2cm from the solenoid's axis
*April 8, 2014*

**Physics**

If an object has a work of 300J and a displacement of 20m, how would I determine the net force?
*April 4, 2014*

**chemistry**

Plan how you would make 100mL of a buffer solution with a pH of 10.80 to be made using only sodium carbonate, sodium hydrogen carbonate and water. You should specify the amount of sodium carbonate and sodium hydrogen carbonate that you would use. Below is what i got up to then...
*April 4, 2014*

**chemistry/science**

Not sure if i posted this but Need help with my pH calculations? 0.10 mol of solid sodium hydrogen carbonate and 0.20 mol of solid sodium carbonate are dissolved in the same beaker of water, transferred to a volumetric ﬂask and made to 250.0 mL. The Ka for HCO3 – ...
*April 4, 2014*

**chemistry**

Need help with my pH calculations? 1) 0.10 mol of solid sodium hydrogen carbonate and 0.20 mol of solid sodium carbonate are dissolved in the same beaker of water, transferred to a volumetric ﬂask and made to 250.0 mL. The Ka for HCO3 – is 4.7 x 10–11. a) ...
*April 4, 2014*

**Physics**

A satellite is given a boost of 540 MJ of energy to move it from its initial orbit at an altitude of 150 km to a higher altitude orbit. If the satellite has a mass of 1.16 ✕ 10^3 kg, what is the new altitude it reaches? Take the mass of the Earth to be 5.97 x 10^24 kg ...
*April 2, 2014*

**Physics-Gravitational Potential Energy**

A satellite is given a boost of 540 MJ of energy to move it from its initial orbit at an altitude of 150 km to a higher altitude orbit. If the satellite has a mass of 1.16 ✕ 103 kg, what is the new altitude it reaches? Take the mass of the Earth to be 5.97 x 10^24 kg ...
*April 1, 2014*

**Physics**

A snowmobile, with a mass of 530 kg, applied a force of 410 N backwards on the snow. a) What force is responsible for the snowmobile’s resulting forward motion? (Hint: Think action–reaction force pairs.) b) If the force of friction on the snowmobile is 187 N ...
*March 28, 2014*

**Physics( Explain and choose right answer) **

A ball on the end of a rope is moving in a vertical circle near the surface of the earth. Point A F T is at the top of the circle; C is at the bottom. Points B and D are exactly halfway between A and C. Which one of the following statements concerning the tension in the rope ...
*March 24, 2014*

**Physics( Explain and choose right answer) **

A 3 kg cat sitting on a 1.5 kg piece of cardboard on a frozen lake wants to jump to shore without touching the ice. If there is no friction between the cardboard and the ice, when the cat jumps. the cardboard will move in the opposite direction with a velocity: A. half as ...
*March 24, 2014*

**Chem**

The density of ethanoic anhydride is 1.092 g/mL. Use this value, and the amount that you used in the laboratory to show that ethanoic anhydride is in excess for your preparation of ASA?, 2.5ml of ethanoic anhydride was used.
*March 14, 2014*

**English**

Which implicit element of the analogy in these lines is analogous to "family worship"? Breakfast over, Aunt Polly had family worship: it began with a prayer built from the ground up of solid courses of Scriptural quotations, welded together with a thin mortar of ...
*March 6, 2014*

**Please help with Chemistry?????**

5.00 mL of 2.00x10^-3M Fe(NO3)3 is mixed with 4.03 mL of 2.00x10^-3M NaSCN and 1.08 mL of 0.1M HNO3, for a total volume of 10.11 mL. a) What is the initial concentration of the Fe(NO3)3 in the mixed solution? b) What is the initial concentration of the NaSCN in the mixed ...
*February 26, 2014*

**Please help with Chemistry?????**

A standard solution with a FeSCN2+ concentration of 1.55x10^-4M has a percent transmittance (%T) of 18.8%. Another solution of unknown FeSCN2+ concentration has a percent transmittance of 44.8%. A) Calculate the absorbance (A) of each solution. B) Using the absorbances ...
*February 26, 2014*

**Chemistry**

A standard solution with a FeSCN2+ concentration of 1.55x10^-4M has a percent transmittance (%T) of 18.8%. Another solution of unknown FeSCN2+ concentration has a percent transmittance of 44.8%. A) Calculate the absorbance (A) of each solution. B) Using the absorbances ...
*February 26, 2014*

**Chemistry**

5.00 mL of 2.00x10^-3M Fe(NO3)3 is mixed with 4.03 mL of 2.00x10^-3M NaSCN and 1.08 mL of 0.1M HNO3, for a total volume of 10.11 mL. a) What is the initial concentration of the Fe(NO3)3 in the mixed solution? b) What is the initial concentration of the NaSCN in the moxed ...
*February 26, 2014*

**Math**

Interest is a concept familiar to most people: every credit card in existence has a term called annual percentage rate (APR), which is an interest rate. Suppose you charged $1,000 to a credit card that has a minimum payment each month equal to the interest owed. Can you figure...
*February 18, 2014*

**Math**

The formula for simple interest is where I is the amount you will pay in interest, r is the rate at which interest will accrue, P is the principal (amount borrowed), and m is the number of times the interest is applied. To solve for the interest rate of your credit card, you ...
*February 18, 2014*

**Math**

Gabe is the human resource manager for the Advanced Scientific Research Lab. He has to record the heights (in centimeters) and weights (in pounds) for each of the scientists in the lab. Height distribution (cm): 178, 163, 174, 186, 154, 167, 167, 181, 159, 165, 177, 191, 158 ...
*February 18, 2014*

**AP chem**

Mostly just setting up my reaction to use for each problem
*February 5, 2014*

**AP chem**

Consider the titration of 50.00 ml .250 M HBr with .100 M Ba(OH)2. What is the pH after the following additions of Ba(OH)2 to the 50 ml of hydrobromic acid? 0 ml. 15 ml. 25 ml. 50ml. 51ml.
*February 5, 2014*

**programming**

using pseudocode debug the following 3 programs // A high school is holding a recycling competition // This program allows a user to enter a student's // year in school (1 through 4) // and number of cans collected // Data is entered continuously until the user wants to ...
*January 13, 2014*

**Physics**

I got it!!! Thank you!!!
*December 24, 2013*

**Physics**

I dont understand it, can you please explain it to me?.. Thanks
*December 24, 2013*

**Physics**

I think it is. and it's not one person, we study in a group. Thank You.
*December 24, 2013*

**Physics**

A pilot, whose mass is 91.0 kg, makes a loop-the-loop in a fast jet. Assume that the jet maintains a constant speed of 125 m/s and that the radius of the loop-the-loop is 0.478 km. What is the apparent weight that the pilot feels (i.e., the force with which the pilot presses ...
*December 24, 2013*

**Physics**

Thank you so much Elena!!
*December 24, 2013*

**Pre-Calc**

Using the difference for formula, find the tan 255. Step by step would be appreciated
*December 18, 2013*

**Math Quiz**

Math Quiz please help fast Write the following ratio in simplest form: 32 min:36 min (1 point) 8:9 8:36 32:9 128:144 2. Marie saved $51. On Wednesday, she spent $8 of her savings. What ratio represents the portion of her total savings that she still has left? (1 point) 43:8 8:...
*December 12, 2013*

**Maths**

Will it be 16x^2-40x+25
*November 18, 2013*

**Maths**

(4x-5)^2
*November 18, 2013*

**Maths**

(5x+4)(5x-4)=
*November 18, 2013*

**physics**

You apply a potential difference of 5.00 V between the ends of a wire that is 2.65 m in length and 0.654 mm in radius. The resulting current through the wire is 17.6 A. What is the resistivity of the wire?
*October 20, 2013*

**Math**

Carla and Candice left from the same place at the same time and rode their bikes in the same direction along a straight road . Candice biked at an average speed that was three-quarters of Carla's average speed. After 2 hours they were 28 miles apart. What was the average ...
*October 7, 2013*

**Math**

The area of each trapezoid is 3 times the area of one triangle. The area of one triangle is six square units. What is the total area of the figure in square units?
*September 23, 2013*

**Algebra word prob**

If you graph the table of values and draw a line through the coordinates, the graph will look like a parabola. Thus the equation is quadratic. Since you don't have a graphing calculator, I will give you the resulting a/b/c values that it comes up with, but the rest is for ...
*September 10, 2013*

**Math**

2. True or false. Suppose the slope of a straight line L is -3/4 and P is a given point on L. If Q is a point on L lying 2 units to the right of P, then Q is situated 3/2 units below P. Prove why.
*August 27, 2013*

**physics **

The Hyperloop is a hypothetical new fast transport system between cities, which works by launching pods that carry people through a very low air pressure tunnel. The Hyperloop reduces friction between the pods and the tunnel by supporting the pod on a cushion of air. This air ...
*August 22, 2013*

**Statistics**

Hola ¿Cuál es el P - value en este problema que escribiste?
*July 29, 2013*

**Math**

A circle of radius 1 is drawn in the plane. Four non-overlapping circles each of radius 1, are drawn (externally) tangential to the original circle. An angle γ is chosen uniformly at random in the interval [0,2π). The probability that a half ray drawn from the centre...
*June 24, 2013*

**Math**

There are 100 runners, each given a distinct bib labeled 1 to 100. What is the most number of runners that we could arrange in a circle, such that the product of the numbers on the bibs of any 2 neighboring runners, is less than 1000?
*June 23, 2013*

**Math**

γ is a permutation on eight elements, though you are not told which permutation it is. If γ is applied to an 8-element set, what is the minimum number of additional times we must apply γ to the resulting set in order to guarantee the set is back in its original ...
*June 18, 2013*

**Physics 1**

A body of mass 6kg moving at 8m/s collides with a stationary body of mass 10kg and sticks to it. Find the speed of the composite body immediately after the impact.
*June 10, 2013*

**Math (Algebra)**

Thanks Steve!
*May 21, 2013*

**Math (Algebra)**

f(x) is a cubic polynomial that satisfies f(1)=f(2)=f(3)=4 and f(0)=0. What is the value of f(7)?
*May 21, 2013*

**Math (Probability)**

Please tell the answer. I'm not able to get it. Thanks.
*May 21, 2013*

**Math (Probability)**

Bret and Shawn are playing a game where each turn the players roll a 20-sided die fair and then add the number they get to their score. The winner is the player with the highest score at the end of the game (there may be a tie). Before the last turn, Shawn is winning by 10 ...
*May 21, 2013*

**Math (Algebra)**

A number is called algebraic if there is a polynomial with rational coefficients for which the number is a root. For example,√2 is algebraic because it is a root of the polynomial x^2−2. The number √2+√3+√5 is also algebraic because it is a root ...
*May 21, 2013*

**Physics**

A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long in seconds does it take for the door to fully...
*May 21, 2013*

**Math (Combinatorics)**

Six boxes labeled 1,2,…,6 are arranged in a line. Seven identical balls are to be placed into the boxes such that for any 1 ≤ k ≤ 6, there are at least k total balls amongst boxes 1,2,…k. How many different placements of the balls into the boxes are ...
*May 21, 2013*

**math**

or 9√970/500.
*May 20, 2013*

**math**

It's 0.5606068140863.
*May 20, 2013*

**Physics**

A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long in seconds does it take for the door to fully...
*May 20, 2013*

**Geometry**

Perimeter of Rectangle = 2L + 2W where: L = length, and W = width Perimeter = 2(8) + 2 (6)= 28 inches Area of Rectangle = L x W Area = (6in)(8in) = 48 inches squared.
*May 20, 2013*

**heeelp MATH**

Yes please Reiny. It would help me a lot. Thanks! :)
*May 16, 2013*

**Math (Geometry)**

ABC is a triangle with a right angle at A. M and N are points on BC such that AM is the altitude, and AN is the angle bisector of ∠BAC. If CN/NB=21, what is CM/MB?
*May 16, 2013*

**Math (Geometry)**

ABC is a triangle with a right angle at A. M and N are points on BC such that AM is the altitude, and AN is the angle bisector of ∠BAC. If CN/NB=21, what is CM/MB?
*May 15, 2013*

**Math (Geometry)**

Thanks hans!
*May 15, 2013*

**Math (Geometry)**

A point P is given outside of a circle Γ. A tangent from P to Γ touches Γ at T with PT=45. A line from P cuts Γ at the 2 points A,B. If PA=25, what is the length of PB?
*May 15, 2013*

**Math (Geometry)**

ABCD is a parallelogram with side lengths AB=15,BC=10 and ∠ADC=75∘. A point P in the interior of the parallelogram is chosen such that ∠APD+∠CPB=180∘. What is the measure (in degrees) of ∠PAD+∠PCB?
*May 15, 2013*

**Math (Probability)**

When Lino submitted an essay for his English class, it was 9 pages long. Lino's essay had errors on pages 2 and 7. If the teacher chose 3 pages uniformly at random to read, then the probability that she didn't read any of the pages with errors can be expressed as a/b ...
*May 15, 2013*

**Math - Maximizing Logarithm**

x and y are positive values satisfying x + y = 1/4. When ln(y^2+4xy+7) attains its maximum (subject to the given constraint), what is the value of 1/xy?
*May 13, 2013*

**algebra**

12(3+y)=5(2y+8)
*May 11, 2013*

**math**

the class room had 100 students.in 200, there were 6 few men than there were woman.how man women were in the classroom in 2010?
*May 9, 2013*

**accounting**

A company was recently formed with $ 50,000 cash contributed to the company by stock-holders. The company then borrowed $ 20,000 from a bank and bought $ 10,000 of supplies on account. The company also purchased $ 50,000 of equipment by paying $ 20,000 in cash and issuing a ...
*May 7, 2013*

**Pre Algerbra**

I invested $3,000, part at 2% and the rest at 5% simple interest. After 1 year, I earned a total of $117 in interest. How much did I invest at each rate?
*April 25, 2013*

**math**

0.941
*April 21, 2013*

**physics**

A radio station on the surface of the earth radiates an EM-wave with an average total power of 50 kilo-watts. Assuming the transmitter radiates equally in all directions (not in real life), find the amplitudes Emax and Bmax detected by a satellite at a distance of 100km from ...
*April 15, 2013*

**physics**

Four acrobats of mass 61.0 kg, 68.0 kg, 62.0 kg, and 55.0 kg form a human tower, with each acrobat standing on the shoulders of another acrobat. The 61.0-kg acrobat is at the bottom of the tower. If the area of each of the 61.0-kg acrobat's shoes is 370 cm2, what average ...
*April 4, 2013*

**Physics**

For safety in climbing, a mountaineer uses a nylon rope that is 55 m long and 0.9 cm in diameter. When supporting a 88-kg climber, the rope elongates 1.4 m. Find its Young's modulus.
*April 4, 2013*

**physics**

A window washer is standing on a scaffold supported by a vertical rope at each end. The scaffold weighs 192 N and is 3.4 m long. What is the tension in each rope when the 708-N worker stands 2.40 m from one end? Smaller tension: ___N Larger tension: ___N
*April 4, 2013*

**Chemistry**

A 7mL triprotic acid was analyzed and found to contain 0.2572 grams of acid, evidence of phosphate group. Find the molecular weight of the acid, and identify acid. Thank you.
*April 3, 2013*

**physics**

I am helping my friend move into his new apartment. During the move, we have to load boxes into the back of his truck. To make it easier to load them, we've set up a metal ramp so that we can slide the boxes up to the deck of the truck. The box shown in the figure has a ...
*April 2, 2013*

**western illinois**

102 = 3.14 x 42.25 x h solve for h
*March 30, 2013*

**Calculus**

The volume of the 3-dimensional structure formed by rotating the circle x^2 + (y-5)^2 = 1 around the x-axis can be expressed as V = a\pi^2. What is the value of a?
*March 27, 2013*

**Physics**

Every once in a while a bird will get hit by a baseball during a baseball game. The longest home runs in baseball land about 500 feet (which is 152.4 meters) from home plate. If these balls leave the bat at a 45 degree angle to maximize their distance, what is the minimum safe...
*March 27, 2013*

**Trigonometry**

ABC is a right triangle with AB = 2, BC = 3\sqrt{5}, AC = 7 and \angle ABC = 90^\circ. If \cos \angle BAC = \frac{a}{b}, where a and b are coprime positive integers, what is the value of a + b?
*March 27, 2013*

**Geometry**

Determine the number of subsets of A=\{1, 2, \ldots, 10\} whose sum of elements are greater than or equal to 28 .
*March 26, 2013*

**Geometry**

ABC is an acute triangle with \angle BCA = 35 ^\circ. Denote the circumcenter of ABC as O and the orthocenter of ABC as H. If AO=AH, what is the value of \angle ABC (in degrees)?
*March 26, 2013*

**Geometry**

ABC is an isosceles triangle where AB = AC and BC = 60. D is a point on BC such that the perpendicular distance from D to AB and AC is 16 and 32, respectively. What is the length of AB?
*March 26, 2013*

**physics**

A cargo plane is moving with a horizontal velocity of vx = +225 m/s at a height of y = 920 m above level ground as shown in the figure below when it releases a package. Ignoring air resistance, how much time will it take the package to reach the ground? (Express your answer to...
*March 26, 2013*

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