Sunday

July 5, 2015

July 5, 2015

Total # Posts: 725

**Physics**

Peter is shooting arrows at a target with a bow. The target is 10m above the arrows launch point and some distance from Peter. If the arrows are shot with initial velocity Vo at 60 degrees with respect to the ground, then they will hit the target at the highest point of their ...
*May 8, 2014*

**Physics**

I got the wrong answer. My answer key says the answer is 7m/s. t = sqrt(20/9.8) = 1.428 d = 1/2(9.8)(1.428)^2 = 10 d*t = 14.28 What am I doing wrong?
*May 8, 2014*

**Math**

Circle the angle(s) that could never be the smallest angle of a triangle. 8 degrees 47 degrees 88 degrees 91 degrees
*May 7, 2014*

**chemistry**

Oh ok, I see what I did wrong, I switched the masses for Electron and Neutron. Ok now we're on the same page. So then to get kg you multiplied 0.813986 amu by 1.66054x10-27 kg = 1.3516563E-27 kg. Then, plug it into the equation E=mc^2 I got 1.216E-10 . Then divide that by ...
*May 2, 2014*

**chemistry**

or no it equals to 12.29. Then i divided it by 1000 because I thought that's how I would get kg
*May 2, 2014*

**chemistry**

No it seems we aren't. So this is what I did to find the P E N of Rb #protons=#electrions=37 (from the periodic table) Neurtrons= 87-37=50 with that I multiplied by their masses. Added them together to get 74.6176. Then I did 86.909187-74.6176 = .01229
*May 2, 2014*

**chemistry**

How much energy in MeV is released to form one atom of 87Rb from protons, electrons, and neutrons if the nucleus has a mass of 86.909187 amu? The masses of the proton, electron and neutron are 1.00728 amu, 0.000549 amu and 1.00867 amu, respectively. 1.602x10-13 J = 1 MeV; 1 ...
*May 2, 2014*

**Algebra - HELP!!!**

Would 21 be negative 10.35, and positive 1.35 Would 20 be negative 11.56 and positive 1.56
*April 22, 2014*

**Algebra - HELP!!!**

I can't! the formatting is odd.
*April 22, 2014*

**Algebra - HELP!!!**

For 20 and 21 are the x values in both negative and the y values positive?
*April 22, 2014*

**Algebra - HELP!!!**

negative 16t to the second power plus 85. :)
*April 22, 2014*

**Algebra - HELP!!!**

– 16 t^2 + 85 (sorry for having to repost so many times)
*April 22, 2014*

**Algebra - HELP!!!**

–16t^2 + 85
*April 22, 2014*

**Algebra - HELP!!!**

Here is a better copy of 11: 11. If an object is dropped from a height of 85 feet, the function h(t) = –16t^2 + 85 gives the height of the object after t seconds. Approximately, when will the object hit the ground? (1 point) 85.00 seconds 69.00 seconds 0.33 seconds 2.30 ...
*April 22, 2014*

**Algebra - HELP!!!**

Can someone help me and check these? 1. Graph the function and identify the domain and range. y = –.5x² (1 point)graph *domain: (–∞, ∞) range: [0, ∞) graph domain: (–∞, ∞) range: (–∞, 0] graph domain: (–∞...
*April 22, 2014*

**Chemistry**

I had conducted an experiment to figure out the percent by mass of baking soda in a mixture by titration. I had to standardize 1.0M HCl. Through the standardization process and the titration curve of the primary standard and the HCl, the molarity has to be found, but is this ...
*April 13, 2014*

**Chemistry**

The overall hydrogen burning reaction in stars can be represented as the conversion of four protons to one alpha particle. Use the data for the mass of H-1 and He-4 to calculate the energy released by this process.
*April 10, 2014*

**Chemistry**

years
*April 10, 2014*

**Math**

I get a black strip every 10 days. A white strip every 20 days, and a red strip every 21 days. I just got all 3 strips. How long 'till I get all of them again on the same day?
*April 9, 2014*

**Science**

A gas sample in a sealed vial originally at 0.6 atm and 300 K, was heated to 450 K. What other property of the gas has changed? What is the value of this property after heating?
*April 7, 2014*

**chemistry**

A gas sealed vial originally at 0.6 atm and 300 K, was heated at 450 K. What other property of the gas has changed? What is the value of this property after heating?
*April 7, 2014*

**chemistry**

calculate the molar weight of Freon-II, of 8.29 liters of its vapor at 200 degrees celcius and 790 mm Hg has a mass of 30.5 g.?
*April 7, 2014*

**ashford**

Football is the best sport. The athletes are amazing, and it is extremely complex. is deductive or inductive
*April 6, 2014*

**Calculus**

Determine whether the series is convergent or divergent. If it is convergent, find its sum. If it is divergent, enter NONE. sum from 1 to infinity of (5^n+4^n)/20^n It is convergent, but I do not know how to find the sum.
*April 3, 2014*

**Calculus**

Determine whether the series is convergent or divergent. If it is convergent, find its sum. If it is divergent, enter NONE. sum from 1 to infinity of 1/e^2n. It is convergent, but I do not know how to solve for the sum.
*April 3, 2014*

**Chemistry**

How does dissolved CO2 in distilled water affect the accuracy of the determination of a NaOH solution's concentration? How is the term acid anhydride applied here? I know you had answered this already, but what if KHP is used to titrate the NaOH. In this experiment KHP was...
*March 29, 2014*

**Chemistry**

In this experiment NaOH is standardized to titrate it with vinegar so thtat the percent by mass of the acetic acid can be determined. How does dissolved CO2 in distilled water affect the accuracy of the determination of a NaOH solution's concentration? How is the term acid...
*March 29, 2014*

**Chemistry**

In this experiment NaOH is standardized to find out the percent by mass of the acetic acid in a sample of vinegar. A student had not allowed the NaOH pellets to dissolve completely before standardizing it with KHP, but when the student refilled the buret with NaOH to titrate ...
*March 29, 2014*

**Chemistry**

Titration was used to determine the molarity of acetic acid in vinegar. A primary standard solution of KHP was used to standardize the NaOH. 1. When performing this experiment, impure KHP was used to standardize the NaOH solution. If the impurity is neither acidic or basic, ...
*March 28, 2014*

**Chemistry**

I got think I got the following questions almost figured, but I just want someone to make sure that I am correct. 1) The whole experiment involves using the ideal gas law to predict the molar mass of an unknown liquid. The formula is molar mass of liquid = gR(0.0821)T(...
*March 28, 2014*

**CHEMISTRY**

The mass of an erlenmeyer flask is 78.639g and the mass of the flask and water is 327.039. If the density of water is 1 g/ml then what is the true volume of the flask? so i had subtracted the mass of just the flask from the mass of the flask and the water and got 248.4. Would ...
*March 28, 2014*

**mat116 algebra**

1-5x-4>-3
*March 21, 2014*

**statistics**

99% of men scored between -52.68 ,64.64 where did 95% of the values for weight relative to the ideal lie?
*March 19, 2014*

**Calculus**

Solve the initial-value problem. y'' - 2y' + y = 0 , y(2) = 0 , y'(2) = 1
*March 16, 2014*

**Calculus**

Solve the boundary-value problem. y'' + 5y' - 6y = 0 , y(0) = 0 , y(2) = 1
*March 16, 2014*

**Chemistry**

3. How does dissolved CO2 in distilled water affect the accuracy of the determination of a NaOH solution's concentration? The CO2 in the distilled water will create a more acidic solution which will affct the determination of NaOH solution's concentration? How is the ...
*March 11, 2014*

**chemistry**

Titration was used to determine the molarity of acetic acid in vinegar. A primary standard solution of KHP was used to standardize the NaOH. 1. When performing this experiment, impure KHP was used to standardize the NaOH solution. If the impurity is neither acidic or basic, ...
*March 11, 2014*

**Math**

Gold medalist, in freestyle skiing, Justine Duford-Lapointe, is trying to get to her hotel. She can travel north and east. The grid is a 5*5 followed by a 2*2, followed by a 8*8. How many ways can she take to her hotel?
*March 3, 2014*

**chemistry**

What is the product for Ni(s) + 2Na^+? I don't think this is possible. Am I wrong?
*March 2, 2014*

**Chemistry: Check my answers please!**

How would each of the following affect the Cr(VI) concentration determined in this experiment? Justify the answers with an explanation. In the experiment, absorption spectroscopy was used to obtain the concentration of Cr(VI) ions. 1) A student adds more standard solution than...
*March 2, 2014*

**Chem**

How would one be able to identify the lambda max of Cr(III) at a concentration less than 70ppm from a graph? I couldn't post the graph, but I don't understand how one would be able to do this? Can you please justify the answer with an explanation? I would want to know ...
*March 2, 2014*

**Chemistry**

How would one be able to identify the lambda max of Cr(III) at a concentration less than 70ppm from a graph? I couldn't post the graph, but I don't understand how one would be able to do this? The graph had the Chromium Absorbance Spectra of 70ppm for Cr(VI) and Cr(III...
*March 2, 2014*

**Chemistry**

How would one be able to identify the lambda max of Cr(III) at a concentration less than 70ppm from a graph? I couldn't post the graph, but I don't understand how one would be able to do this? The graph had the Chromium Absorbance Spectra of 70ppm for Cr(VI) and Cr(III...
*March 2, 2014*

**Chemistry**

How would each of the following affect the Cr(VI) concentration determined in this experiment? Justify the answers with an explanation. In the experiment, absorption spectroscopy was used to obtain the concentration of Cr(VI) ions. 1) A student adds more standard solution than...
*March 2, 2014*

**chemistry**

1) List a series of tests that would determine the order of activity (least active to most active) for Zn, Mn, and Ag. 2) What would be the reaction for the addition of excess OH- ions to Mg(NO3)2 and Cu(NO3)2? This is a complex ion forming reaction. Would the complete ionic ...
*March 2, 2014*

**Chemistry**

Why is a blank solution used in absorption spectroscopy? I know it is to nullify the reflection, refraction, and diffraction that occurs, but if the blank solution was a dilute solution rather deionized water, how would the concentration of Cr(VI)in a sample be affected?
*February 25, 2014*

**Chemistry**

In an emission spectroscopy, when trying to identify the most intense emission line for an ion, does one have to identify it using the wavelength and the intensity?
*February 23, 2014*

**Chemistry**

In this experiment absorption spectroscopy is conducted to detect Cr(VI)in aqueous solutions and with it the concentration of Cr(VI). How would each of the following affect the Cr(VI) concentration determined in this experiment? Explain the answer. 1. A student adds more ...
*February 23, 2014*

**Math**

Find the LCM of: 72 and 99 72 and 54
*February 22, 2014*

**chemistry**

What is the mass of a sample of ammonia that contains 0.750 moles of hydrogen atoms? The answer is 4.26g, but I do not know how to set up the equation.
*February 22, 2014*

**Math**

No. I need help
*February 19, 2014*

**Math**

Three pigs and two piglets weigh 32 kg. Four pigs and five piglets weigh 59 kg. What is the weigh of one pig and one piglet? A) 13 kg B) 91 kg C) 7 kg D) none of these
*February 19, 2014*

**Chemistry**

1. A student uses 6M HCl solution contaminated with Al(NO3)3 to wash the nichrome wire in between recordings of emission spectra for the different known and unknown metal ion solutions. The emission energies for the aluminum are 3.90x10^-19 J/atom, 3.58x10^-19 J/atom, and 2....
*February 16, 2014*

**Math **

Mr.Fox's fourth grade class of 20 students had an average of 72% on their last test. However, Rose's mark of 76% had been incorrectly recorded as 56 %. What was the correct class average for the test? A) 82% B) 80% C)73% D) 62%
*February 16, 2014*

**Math**

Find the lowest common multiple for 16 and 20
*February 16, 2014*

**trigonometry**

If a tree casts a shadow of 12 feet at the same time that 6 foot person casts a shadow what is the length of the three to the nearst foot
*February 8, 2014*

**Calculus**

A steady wind blows a kite due west. The kite's height above ground from horizontal position x = 0 to x = 60 ft is given by the following. y= 155-(1/40)(x-50)^2 Find the distance traveled by the kite.
*February 4, 2014*

**Calculus**

Find the distance traveled by the kite
*February 4, 2014*

**Calculus**

A steady wind blows a kite due west. The kite's height above ground from horizontal position x = 0 to x = 60 ft is given by the following. y= 155-(1/40)(x-50)^2
*February 4, 2014*

**Calculus**

Use Simpson's Rule with n = 10 to estimate the arc length of the curve. y = tan x, 0 < x < π/9
*February 4, 2014*

**MATH**

OK, Thanks!
*February 4, 2014*

**MATH**

Select the measure of the complement or supplement of the angle. If there is no complement or supplement, select no complement or supplement. 55.1° 124.9° 119.9° 49.9° no complement or supplement
*February 4, 2014*

**English ~CHECK MY WORK PLEASE~**

*Please Note: the the answer with stars next to them are my answers. 1. Imagine you have been asked to read another article about gymnasts. It has the following title and subheads: Title: Gymnasts: For the Love of the Sport Subhead #1: The Naysayers Subhead #2: Lasting ...
*February 4, 2014*

**Art ~ Goya & His Painting **

What message was goya trying to send when he painted the family of King Carlos IV?
*February 3, 2014*

**chemistry**

The laboratory tech accidentally mixed NaHCO3 with BaCl2-2H2O instead of KCl when preparing unknown mixture for this experiment. How would this mistake affect the calculated percentage of NaHCO3 in the mixture? Justify answer with an explanation. Is it still possible to ...
*February 2, 2014*

**chemistry**

A student dried a wet crucible with a Kimwipe. A piece of Kimwipe was left clinging to the inside wall of the crucible, The student did not see the piece of Kimwipe when adding the NaHCO3-KCl mixture to the crucible. The crucible ans its contents were weighed and subjected to ...
*February 2, 2014*

**Chemistry**

A student cleaned a crucible with HCl. After pouring the HCl into the waste container, the crucible was neither rinsed with water or dried before the student added the NaHCO3 and KCl mixture. The crucible contained some residual HCl. How would this experimental error affect ...
*February 2, 2014*

**Art ~ Goya & His Painting **

What message was Goya trying to send when he painted Charles the IV and his family?
*January 31, 2014*

**Science ~ Structures and Properties of Matter**

SO Sorry !
*January 28, 2014*

** Science ~ Structures and Properties of Matter**

1) Both carbon dioxide and water are pure substances. How are they similar to each other? A. both substances have a set ratio of atoms that cannot be separated by physical means. B. both substances have a set ratio of atoms that can be separated by physical means. C. both ...
*January 28, 2014*

**science ~CHECK MY WORK PLEASE~**

So Sorry!!!
*January 28, 2014*

**Science ~CHECK MY WORK PLEASE~**

SO SORRY!
*January 28, 2014*

**Calculus**

The figure shows graphs of the marginal revenue function R ' and the marginal cost function C ' for a manufacturer. (Recall from Section 4.7 that R(x) and C(x) represent the revenue and cost when x units are manufactured. Assume that R and C are measured in thousands ...
*January 25, 2014*

**Calculus**

a)Find the number a such that the line x = a bisects the area under the curve y= 1/x^2, 1<x<3. a=3/2 b)Find the number b such that the line y = b bisects the area in part (a) b=?
*January 25, 2014*

**Calculus**

Sketch the region and find its area. S = {(x,y) | x > -6, 0 < y < e-x/2}
*January 25, 2014*

**Math**

32. The area of a square postage stamp is 81/100 in. to the second power. What is the side length of the stamp? 33. The area of a square boxing ring is 484 ft. to the second power. What is the perimeter of the boxing ring?
*January 23, 2014*

**physics**

A tennis ball has a mass of 0.057 kg. A professional tennis player hits the ball hard enough to give it a speed of 52 m/s (about 117 miles per hour.) The ball moves toward the left, hits a wall and bounces straight back to the right with almost the same speed (52 m/s). As ...
*January 23, 2014*

**physics**

A 0.55 kg block of ice is sliding by you on a very slippery floor at 4 m/s. As it goes by, you give it a kick perpendicular to its path. Your foot is in contact with the ice block for 0.0025 seconds. The block eventually slides at an angle of 23 degrees from its original ...
*January 23, 2014*

**American history**

B
*January 17, 2014*

**algebra**

How much of the 50% and 80% solutions does the teacher have?
*January 17, 2014*

**Physics**

Okay, I figured out the volume, I just need help finding the tension. What should I do to find that?
*January 17, 2014*

**Physics **

I'm super confused about how to approach this problem. Please help. A ball of Styrofoam (ρ = 100 kg/m3) is totally submerged in water. The ball has a mass of 300.0 g What is the volume of the ball? If a string holds the ball when it’s in the water, what’s ...
*January 17, 2014*

**math**

p= 20x where p is equal to the number of pens, and x is equal to the number of boxes that Sheila has purchased.
*January 17, 2014*

**math**

There isn't a table in Part A. This means that if Diana practices for 3 hours she will win 10 tennis matches. Part B = 10 And for Part C just plug in a number for b and put it in place for x. For example if she practiced for 2 hours the equation would look like this 3(2)+1...
*January 17, 2014*

**math**

A, because all sides of a square are the same length. If the width of the square is 3 then the length will be 3. LxW=area 3x3=9 so it's A.
*January 17, 2014*

**physics**

A spring of stiffness 127 N/m, and with relaxed length 0.19 m, stands vertically on a table, as shown in the figure. Instead of compressing the spring with a heavy block, with your hand you push straight down on the spring until your hand is only 0.14 m above the table. (...
*January 17, 2014*

**World Geograpy**

1. Which of the following were the main proponents of NAFTA? A. Environmentalists B. Human rights groups C. Labor unions D. Large corporations 2. Which of the following is the primary subsistence crop in Latin America? A. Potatoes B. Beans C. Corn D. Wheat 3. Among the ...
*January 2, 2014*

**World Geograpy**

1. With respect to global connections, association with _______ offers the brightest immediate future for many African countries. A. India B. the European Union. C. China D. the United States. 2. Slum areas called shantytowns occur in _________ major African cities, housing ...
*January 2, 2014*

**World Geograpy **

1. With regard to British influences on India, which of the following statements is true? A. The common name for the British Indian Empire was the "British Raj." B. The British East India Company ruled India after a sepoy rebellion in 1867. C. The British Indian Army...
*January 2, 2014*

**chem**

7.75 litres of radon gas is at 1.55 atm and -19 degrees c what is the volume at stp
*December 10, 2013*

**Language Arts**

What did Thura’s family and Zdenko’s parents choose to do when they were faced with overwhelming conflicts?
*December 9, 2013*

**Math**

thank you
*December 3, 2013*

**Math**

the diameter of the pizza was 14 inches. What was the ratio of the radius to the diameter of the pizza?
*December 3, 2013*

**Principles of Finance **

.A thirty year US treasury bond has a 4.0 percent interest rate.In contrast, a ten year Treasury bond has an interest rate of 2.5 percent. A maturity risk premium is estimated to be 0.2 percentage points for the longer maturity bond. Investors expect inflation to average 1.5 ...
*November 12, 2013*

**Math**

Thank you again and have a good night!
*November 11, 2013*

**Math**

Also 25x7=175
*November 11, 2013*

**Math**

24x10=240
*November 11, 2013*

**Math**

Estimate using compatible numbers 24x8
*November 11, 2013*

**Math**

Thank you!
*November 11, 2013*

**Math**

Estimate using compatible numbers 611÷14
*November 11, 2013*