Saturday

October 25, 2014

October 25, 2014

Total # Posts: 752

**Physics**

A projectile is launched upward at 26m/s at 30 degrees from the horizontal. The whole path of the projectile takes place over level ground. How much time will the projectile be in the air?
*September 28, 2014*

**Physics**

A cat jumps on to a railing at a height of 1.20 m above the ground. He jumps at an angle of 70 degrees relative to the floor. How fast does he have to be moving when he leaves the floor in order for him to make it up to the railing?
*September 18, 2014*

**Physics**

A basketball player shot a ball. It left his hand at a height of 2.05 m above the court at an angle of 40 degrees relative to horizontal, what initial speed did the ball have if it hit "nothing but net" at the basket 4.50 m away? Assume the rim is 3.05 m above the ...
*September 18, 2014*

**Physics**

A ball leaves a kicker's foot with a velocity of 23.0 m/s and at an angle of 40 degrees up from the ground, how far did the ball travel before being caught by another player?
*September 18, 2014*

**Physics**

The swim portion of a triathlon takes place in a river and is an out-and-back course. The river has a steady current that is 0.400 m/s and the athletes swim against the current for 750m before returning and swimming with the current for the second 750m. If one competitor can ...
*September 18, 2014*

**geometry**

If ac=5x-16 and gf = 2x-4 then af =
*September 3, 2014*

**Calculus - Simpson's Rule and Arc Length**

Can any show me step by step on how to get this? I keep on getting different answers... Thank You! Use Simpson's rule with n=10 to estimate the arc length of y=x^(-1/3), for 1 <= x < 6.
*July 31, 2014*

**mathematics**

4 quarters of x is 36. X is equal to A)9 B)50 C)144 D)40
*June 8, 2014*

**project**

Virginia ratified the constitution with the help of all of the following men EXCEPT: A.Washington B.jefferson C.henry D.Madison
*May 6, 2014*

**Calc 2**

i know that for 3/k(k+1)(k+2) I would use partial fraction representation
*April 16, 2014*

**Calc 2**

find the sum of the series: sum from k=1 to infinity [(3/k(k+1)(k+2))+(-2/3)^k]
*April 16, 2014*

**Calculus II**

Compute the first 5 terms of the sequence: {b(n)}n=1-> infinity = nsqrt(6n) + (5/6)^n. ((that is:(Bsub(n))from n=1 to infinity = nth root of 6n + (5/6)raised to n.)) If the sequence converges, find the limit.
*April 15, 2014*

**Calculus II**

Consider the sequence: (a,sub(n))={1/n E(k=1 to n) 1/1+(k/n)} Show that the limit(as n-> infinity) A(sub(n))= ln 2 by interpreting a(sub(n)) as a Reimann Sum of a Definite Integral.
*April 15, 2014*

**Calc 2**

Consider the sequence: (a,sub(n))={1/n E(k=1 to n) 1/1+(k/n)} Show that the limit(as n-> infinity) A(sub(n))= ln 2 by interpreting a(sub(n)) as a Reimann Sum of a Definite Integral.
*April 14, 2014*

**Calculus II**

Compute the first 5 terms of the sequence: {b(n)}n=1¨‡ = nã6n + (5/6)^n. ((that is:(Bsub(n))from n=1 to infinity = nth root of 6n + (5/6)raised to n.)) If the sequence converges, find the limit.
*April 14, 2014*

**calc 2**

my professor is killing me....
*April 7, 2014*

**calc 2 **

(last one) ... Let f(t) be a function defined for all values of t. The Laplace Transform of f(t) is defined by: F(s)= ç[∘,‡](e^-st(f(t))dt). If the improper integral exists, Find the Laplace Transform for f(t)= sinhat
*April 7, 2014*

**Calc2**

Let f(t) be a function defined for all values of t. The Laplace Transform of f(t) is defined by: F(s)= ç[∘,‡](e^-st(f(t))dt). If the improper integral exists, Find the Laplace Transform for F(t)=t^2.
*April 7, 2014*

**Calculus II**

the gamma function r(x) is defined by r(x)= integral from 0 to infinity of x^n-1(e^-1)dx where n>0. Use integration by parts to show that r(n+1)=nr(n).
*April 7, 2014*

**Calculus II**

the gamma function r(x) is defined by r(x)= integral from 0 to infinity of x^n-1(e^-1)dx. find r(1), r(2), r(3)
*April 6, 2014*

**Calculus II**

using integration by partial fraction, prove that pi + integral from 0 to 1 of x^4(1-x)^4/1+x^2 = 22/7
*April 6, 2014*

**Physics**

2.3) The question says "range of speeds", so i was expecting a quadratic formula.( What do you mean by reversing mu?
*March 31, 2014*

**Physics**

@Damon: I don't understand why that is the answer for 2.1
*March 31, 2014*

**Physics**

I need to check my answers for the following: An Aston Martin V8 Vantage sports car has a maximum “lateral acceleration” of 0.96 “g’s”, after which the car begins to skid out of its turn. 2.1 Calculate the coefficient of static friction between the car...
*March 31, 2014*

**chemistry**

how much heat is required when 6.00g of water is melted at its melting point
*March 24, 2014*

**Calc 2**

Find the length of the curve y^2=x^3 from the origin where the tangent line makes an angle of 45 degrees with the x-axis.
*February 26, 2014*

**world geography/geography**

The forests of the Pacific Northwest are just one of the many different ______________ in the United States where many people work in the same industry. A. elevation regions<<<< B. political regions (C. climate regions)< got this one wrong D. economic regions
*February 25, 2014*

**algebra**

A+0=a
*February 22, 2014*

**Calculus II - Trapezoidal Rule **

Find the error resulting from approximation by Trapezoidal Rule: integral (from 0 to 1) sqrt(1+ x^3) dx .... compute the results for n=8
*February 17, 2014*

**Calculus II - Simpson's Rule **

Find the Error resulted from approximation by Simpson's Rule: integral (from 0 to 1) sqrt( 1+x^3) dx ... compute the result for n=8
*February 17, 2014*

**Calculus II**

okay, i'm just not exactly sure where to start in trying to prove this though.
*February 17, 2014*

**Calculus II**

show that; given any three non-collinear points (x1,y1), (x2,y2), (x3,y3) there is a parabola p(x)=Ax^2+ Bx + c , containing the three points.
*February 17, 2014*

**Math**

Could someone help me with these questions? Thanks! a) A cargo plane left Vancouver, British Columbia (time zone −8) at 3:00 p.m. on a Monday. The plane ﬂew for 11 h to Paris, France (time zone +1). At what local time and on what day did the plane land in Paris? b...
*February 5, 2014*

**Physics Please check my answers**

When I did it, I saw that 8 was true, is that right?
*February 4, 2014*

**Physics Please check my answers**

were the others correct?
*February 4, 2014*

**Physics Please check my answers**

A sound of 7 kHz frequency is well within the normal hearing range of most people. True. False. << 2. Sound is a transverse compression wave. True. False.<< 3. The decibel level of a sound can have a negative value. True.<< False. 4. The Doppler effect occurs...
*February 4, 2014*

**Physics Please check my answers**

Sorry, I forgot to put my answers in. 1. Complete reflection is the special case of refraction at an angle of 180. True. << False. 2. A resonant frequency is the same as a natural frequency. True. << False. 3. For a standing wave, the number of segments is an ...
*February 3, 2014*

**Physics Please check my answers**

1. Complete reflection is the special case of refraction at an angle of 180. True. False. 2. A resonant frequency is the same as a natural frequency. True. False. 3. For a standing wave, the number of segments is an integer equal to the number of half-wavelengths. True. False...
*February 3, 2014*

**Physics Please check my answers**

Were the first 2 correct?
*February 3, 2014*

**Physics Please check my answers**

1. A fluid can only be a liquid. True << False 2. One atmosphere is equal to 14.7 psi. True << False 3. In a fluid, pressure depends on the density of the fluid and the depth. True False << 4. Pascal's Principle says that the buoyant force on an object ...
*February 3, 2014*

**Physics Please check my answers**

It's possible for a body to have both rotational and translational motion at the same time. True. << False. 2. The moment of inertia of an object would be different on the surface of the earth than on the surface of the moon. True. << False. 3. The moment of ...
*February 3, 2014*

**Physics**

so basically 39%?
*February 1, 2014*

**Physics**

I got 38.88 is that correct?
*February 1, 2014*

**Physics**

A heat engine absorbs 126 kcal of heat and exhausts 77 kcal of heat in each cycle. Calculate the efficiency (as a percentage)
*February 1, 2014*

**Physics**

An ideal gas heat engine operates in a Carnot Cycle between temperatures of 266 and 115°C. It absorbs 4250 cal per cycle at 266°C. What is its efficiency as a percentage
*January 31, 2014*

**Physics**

A heat engine absorbs 126 kcal of heat and exhausts 77 kcal of heat in each cycle. Calculate the efficiency (as a percentage)
*January 31, 2014*

**Physics**

How much (in Celsius degrees) is the temperature of 1.3 kg of alcohol raised by adding 4.1 kcal of heat? The following piece of information may come in handy: specific heat of alcohol is 0.58 kcal/kgC.
*January 31, 2014*

**Math (PreCal)**

Kurt wants to sail his boat from a marina to an islnd 15 miles east of the marina. Along the course, there are several small islands they must avoid. He sails first on a heading of 70 degrees and then on a heading of 120 degrees. What is the total distance he travels before ...
*January 13, 2014*

**chemsitry**

The molecular geometry of POCl3 is tetrahedral. What hybridization does this indicate for the central P atom? Why is the answer spy?
*December 11, 2013*

**Chemistry**

60.0 mL of O2 was collected over water at a total pressure of 755 torr and a temp of 25C. The vapor pressure of water at 25C is 24 torr. How many moles of O2 were collected? Could you please explain and show the steps? I know the answer is 2.36x10^-3.
*December 11, 2013*

**Chemistry**

What will be the concentration of the solution formed when 5.72mL of 8.50M HCl is diluted to 250mL?
*December 10, 2013*

**Chemistry #4**

What is the concentration of a solution formed by dissolving 10.0g of ammonium acetate in enough water to form 150.0mL of solution? Could someone please explain and show me how to do this? I have the answer= .865M But I am not sure exactly how?!
*December 9, 2013*

**Chemistry**

H(f) Cl= 121.3 kj H(f) C= 716.7 H(f) CCl4= -95.7 calculate the average molar bond enthalpy of the carbon-chlorine bond in a CCl4 molecule. I have tried to figure it out and keep getting the wrong answer. Please help!
*November 25, 2013*

**Physics**

A pulley of mass mp , radius R , and moment of inertia about its center of mass Ic , is attached to the edge of a table. An inextensible string of negligible mass is wrapped around the pulley and attached on one end to block 1 that hangs over the edge of the table. The other ...
*November 24, 2013*

**Yanii**

This anomalous expansion plays an important role by only freezing the upper layer in lakes and rivers. During winter months in colder countries the outside or atmospheric temperature is very low - it drops to below freezing - and the upper layers of water in the lakes and ...
*November 23, 2013*

**chemistry**

Please I need help in knowing how to solve this. I know I need to take the antilog of something but don't know what.What is the values of [H3O+] for a solution with [OH−]=1×10−5M?
*November 22, 2013*

**chemistry**

5.00×10−3mol of HBr are dissolved in water to make 15.0L of solution. What is the concentration of hydroxide ions, [OH−], in this solution?
*November 21, 2013*

**chemsitry help again please**

Write the formula of the conjugate base for acid HClO2 .
*November 19, 2013*

**networking**

A firm is assigned the network part 128.171 It selects a 10-bit subnet part a) draw the bits for the first four octets of the IP address of the first host on the first subnet. b) convert this answer to dotted decimal notation. c) Draw the bits for the second host on the third ...
*November 14, 2013*

**chemistry**

I am having a hard time with this problem. I was wondering where I went wrong. The problem says The equilibrium constant, Kc, for the reaction of H2 and N2 is 1.7×10^2 at 225 ∘C. 3H2(g)+N2(g)←→2NH3(g) If the system at equilibrium contains 0.16M H2 and 0...
*November 13, 2013*

**Chemistry**

If the wavelength if determined to be 0.018 nm, at what velocity is the electron traveling? (The mass of an electron is 9.11x10^-31kg) I know the answer is 4.0x10^7 m/s, but i cannot figure how they got this. Could someone please explain it to me and show me? Thanks!!
*November 11, 2013*

**chemistry**

I am still having trouble with this question It says What is the molarity of a solution containing 18.0g of KCl in 262mL of KCl solution? When I calculated it I got .92154 m. I had changed 18 g into moles and 262 ml into liters and then divided the moles into liters. I was ...
*November 7, 2013*

**Chemistry Please :/**

When a metal was exposed to light at a frequency of 4.26× 1015 s–1, electrons were emitted with a kinetic energy of 4.50× 10–19 J. What is the maximum number of electrons that could be ejected from this metal by a burst of light (at some other frequency) ...
*November 7, 2013*

**Chemistry #13**

When a metal was exposed to light at a frequency of 4.26× 1015 s–1, electrons were emitted with a kinetic energy of 4.50× 10–19 J. What is the maximum number of electrons that could be ejected from this metal by a burst of light (at some other frequency) ...
*November 6, 2013*

**chemistry volume problem**

Can someone please explain to me how to do this?! I am completely lost. Calculate the volume indicated for each of the following: liters of a 2.00M KCl solution to obtain 0.600mol of KCl.
*November 6, 2013*

**Chemistry #4**

How long does it take (in minutes) for light to reach Earth from the Sun, a distance of 1.589 × 108 km?
*November 4, 2013*

**Physics HELP!!**

A small ball of mass m=0.60 kg hangs from a massless string of length l= 1.2 m. The ball travels in a vertical circle and its speed at the bottom is v0= 6.0 m/s (see figure). Neglect all friction and air drag, and use g=10 m/s2 for the gravitational acceleration. The ball is ...
*November 4, 2013*

**chemistry**

How many grams (of mass m) of glucose are in 355mL of a 5.50% (m/v) glucose solution?
*November 4, 2013*

**PLEASE HELP!! ;(**

I'm so confused
*October 28, 2013*

**Chemistry #17**

I have no idea!
*October 28, 2013*

**Chemistry #17**

When a 5.00g sample of KBr is dissolved in water in a calorimeter that has a total heat capacity of 3.982 kJ-K, the temperature decreases by .210 K. Calculate the molar heat of solution of KBr. =____kJ/mol
*October 28, 2013*

**Chemistry #25**

Could you do the first one for me so I can see please?
*October 28, 2013*

**Chemistry #25**

Use enthalpy of formation data to calculate the number of moles of CO2(g) produced per megajoule of heat released from the combustion of each fuel under standard conditions (1atm and 25 degrees C) a. coal C(s, graphite) = _____mole-MJ b. natural gas, CH4(g)= c. propane, C3H8(g...
*October 28, 2013*

**Chemistry #27**

Sorry i meant H(rxn) (of the reaction)
*October 28, 2013*

**Chemistry #27**

Given that: H2 (g) + F2 (g) ---> 2HF (g) H(rxn)= -546.6 kJ 2H2 (g) + O2 (g) ---> 2H2O (l) H (rxn)= -571.6 kJ calculate the value for H(run) for... 2F2(g) + 2H2O (l) ---> 4HF (g) + O2 (g) _____kJ?
*October 28, 2013*

**Chemistry**

A certain gas has a density of 1.053 g/L at 25C and 752 mmHg. What is the molar mass of this gas?
*October 15, 2013*

**Chemistry #11**

Sorry I meant .79= density
*October 14, 2013*

**Chemistry #11**

A solution of ethanol (C2H5OH) is prepared by dissolving 35.0 ml of ethanol in enough water to make 120.0 ml of solution. What is the molarity of the ethanol in this solution? 46.07 g= molar mass of ethanol .079 g/ml=density
*October 14, 2013*

**Chemistry**

What is the sodium concentration when a solution is formed by mixing 60.0 ml of 0.150 M sodium carbonate with 75.0 ml of 0.225 M sodium bicarbonate?
*October 14, 2013*

**AP Chemistry**

1 atm= 101325 Pa 1 atm= 101.325 kPa
*October 13, 2013*

**Chemistry #27**

If He(g) has an average kinetic energy of 4410 J/mol under certain conditions, what is the root mean square speed of O2(g) molecules under the same conditions?
*October 13, 2013*

**Chemistry #26**

where R=8.314 J/(mol·K) and ℳ is molar mass in kilograms per mole. Note that a joule is the same as a kg·m2/s2. What is the rms speed of N2 molecules at 335 K? What is the rms speed of He atoms at 335 K?
*October 13, 2013*

**Chemistry #25**

Calculate the average translational kinetic energy (sometimes just called average kinetic energy)...for one mole of gas at 381 K.
*October 13, 2013*

**Chemistry #30**

A sample of Br2(g) takes 10.0 min to effuse through a membrane. How long would it take the same number of moles of Ar(g) to effuse through the same membrane?
*October 13, 2013*

**Chemistry**

If a solution containing 52.044 g of mercury(II) chlorate is allowed to react completely with a solution containing 15.488 g of sodium sulfate, how many grams of solid precipitate will be formed? How many grams of the reactant in excess will remain after the reaction? I have ...
*October 13, 2013*

**Chemistry**

I have figured out that 32.34 grams of solid precipitate will form but I'm not sure how to figure out the grams of the reactant in excess? I thought it was 22.01 g but that isn't right.
*October 13, 2013*

**Chemistry**

If a solution containing 52.044 g of mercury(II) chlorate is allowed to react completely with a solution containing 15.488 g of sodium sulfate, how many grams of solid precipitate will be formed? How many grams of the reactant in excess will remain after the reaction? I have ...
*October 13, 2013*

**Chemistry**

Oh dern, okay thanks!
*October 13, 2013*

**Chemistry**

Enter the net ionic equation, including phases, for the reaction of AgNO3(aq) with BaO(aq). Is it... Ag+O2--->AgO?
*October 13, 2013*

**Chemistry- dilution**

51.0 mL of a 1.20 M solution is diluted to a total volume of 248 mL. A 124-mL portion of that solution is diluted by adding 125 mL of water. What is the final concentration? Assume the volumes are additive.
*October 13, 2013*

**Chemistry**

What is the pressure of the gas in a manometer if the height in between is 71mm and the atmospheric pressure is 761mmHg?
*October 12, 2013*

**Chemistry 22**

Table salt NaCl and sugar C12H22O11 are accidentally mixed. A 6.00 g sample is burned and 2.90 g of CO2 is produced. What was the mass percentage of the table salt mixture? Could you please show me all the way through if you can?
*October 5, 2013*

**Chemistry 10**

reaction of AgNO3 with BaO... Would it be Ag^+ + O^---> AgO (s)
*October 5, 2013*

**Chemistry**

NaHCO3 (s) + HC2H3O2 (aq) ---> ?
*October 4, 2013*

**Chemistry**

Oh, Got it! .168?
*October 4, 2013*

**??**

.156 M?
*October 4, 2013*

**Chemistry**

The limiting reactant is the KOH with .069 moles right? So then I go from mol KOH to grams of K2SO4?
*October 4, 2013*

**Chemistry**

Write the balanced neutralization reaction between H2SO4 and KOH in aq. solution. .350 L of .410 M H2SO4 is mixed with .300 L of .230 M KOH. What concentration of sulfuric acid remains after neutralization? ______ M H2SO4
*October 4, 2013*

**Chemistry**

6.34 g??
*October 4, 2013*

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