# Posts by jessica

Total # Posts: 3,330

**math**

To qualify for a special program at university, sharma had to write a standardized test. The test had a maximum score of 750, with a mean score of 540 and a standard deviation of 70. Scores on this test were normally distributed. Only those applicants scoring above the third ...

**Chemistry**

A compressed air tank carried by scuba divers has a volume of 9.5 L and a pressure of 140 atm at 20?C. If the gas was instead in a cylinder with a floating, massless, frictionless piston, what would the volume of the gas be (in liters) at STP? Express the volume in liters to ...

**Chemistry**

When a 3.80 g sample of magnesium nitride (MW 101g/mol) is reacted with 3.30 g of water, 3.60 g of MgO is formed. What is the percent yield of this reaction? Mg3N2 + 3 H2O --> 2 NH3 + 3 MgO

**AP Chemistry Help!**

I had to conduct an experiment to find the enthalpy of reaction for : 4Fe + 3O2 + 6H2O ----> 4Fe(OH)3 In the experiment , I started with an inital temperature of 22.3 C and edned with 36.7 C so the delta T is +14.4C. Now it's telling me to calcualte the delta Hrxn for ...

**Physics**

The block of mass 2.13615 kg has an acceler- ation of 3.7 m/s2 as shown. What is the magnitude of F? Assume the acceleration due to gravity is 9.8 m/s2 and the surface is frictionless. Answer in units of N.

**physics**

A child with a mass of 17 kg sits at a distance of 1 m from the pivot point of a seesaw. Where should a 15 kg child sit to balance the seesaw?

**physics**

Damon thanks for the push! The answer is number 2...:)

**physics**

The work that a force does by acting on an object is equal to what? 1) the product of force (in the direction of motion) and distance and is negative if the force and motion are in the same direction 2) the product of force (in the direction of motion) and distance and is ...

**Math**

Just by reading the steps I am lost please if someone can help me i am studying for a quizz on Friday but I want to undestand . All I understand is the meaning I can see any expression multiplied by 1 is equivalent to original expression but I am lost with these questions. ...

**Math**

Ok I am lost I need help. Describe how you can use a generic rectangle to multiply two numbers. Give an example. I'm just thinking of 22×35

**English**

Please help to understand this assignment. Like sections, introduction and subheadings. Ideas. How should I start with the subheadings/sections? First introduction and overview? Thank you! Building Communities: Do a situational analysis of the police department in the city ...

**Math Question**

Answer is c 8,000 machine I

**Math**

Sorry I ment 67.50 each

**Math**

$67.25each 60 for each ticket+5 (per ticket)+ $2.50 (each 4/$10)

**Physics**

Josh is standing on the roof of the school 12 meters directly above James who kicks a soccer ball straight up with an initial velocity of 15 m/s. If Josh catches the ball on the way up, how long will the ball take to reach him? If he misses it on the way up and catches it on ...

**Physics**

Suppose Jessica drops a rock from a hot air balloon 200m above the water. how long does it take the rock to fall (a) the first 100 meters and (b) the second 100 meters?

**math**

Jake filled his 50 gallon bathtub in 5 minutes. How fast was the water flowing?

**physics**

An 76 kg satellite orbits a distant planet with a radius of 4500 km and a period of 280 min. From the radius and period, you calculate the satellite's acceleration to be 0.63 m/s2. What is the gravitational force on the satellite?

**math**

Assume ang interes rate of 5% compounded semiannually ang 20 semiannual payments to settle the loan

**physics**

What changed Newton's original work on the movement of the Moon around the Earth into the law of universal gravitation? 1) his conclusion that the same laws applied to all objects, no matter how small 2) his connection of gravitation to his first law 3) his connection of ...

**physics**

Never mind Scott, I see my mistake. I forgot to do the last step ( multiply). Thank you for your help!

**physics**

Scott, that is the answer that I came up with and I got it wrong.

**physics**

Two spacecraft in outer space attract each other with a force of 4 N. What would the attractive force be if they were one-eighth as far apart?

**Physics**

Two blocks of masses 11 kg and 8.0 kg are connected together by a light red string and rest on a frictionless level surface. Attached to the 8-kg mass is a light blue string, which a person uses to pull both blocks horizontally. If the two-block system accelerates at 0.5 m/s2...

**Chemistry**

Identify the oxidation-reduction reactions among the following: 1. Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s) 2. 2Na(s) + Cl2(aq) → 2NaCl(s) 3. 2Mg(s) + O2(g) → 2MgO 1 and 2 only 2 and 3 only 1 and 3 only All of 1, 2, and 3 None of 1, 2, and 3

**Physics**

Please help..... When something is thrown over a large distance (on earth ) what new factor comes into play? 1- The decrease in gravity over long distance 2- The increase in gravity over long distance 3- The tendency of thrown objects to fall to the ground 4- The difference ...

**algebra**

A candidate for public office has claimed that 60% of voters will vote for her. If 5 registered voters were sampled, 1. What is the probability distribution function for this voting? 2. What is the probability that exactly 3 would say they favor this candidate? 3. Calculate ...

**algebra**

candidate for public office has claimed that 60% of voters will vote for her. If 5 registered voters were sampled,

**American Government**

Has anyone taken this test? Please help!!!!

**American Government**

12. Read this excerpt from the U.S Constitution. To declare War, grant Letters of Marque and Reprisal, and make Rules concerning Captures on Land and Water; To raise and support Armies, but no Appropriation of Money to that Use shall be for a longer Term than two years; -...

**Math**

Find the percent change. Round to the nearest percent. 215 1/2 lb to 133 1/4 lb $315.99 to $499.89

**American Government**

Thanks!

**American Government**

1. Thomas Hobbes and John Locke were European philosophers who influenced American founding documents with which theory? A. social contract theory B. divine right of kings theory C. no taxation without representation theory D. equal pay for equal work theory

**Biology**

Oh, I forgot to add that. :D My answers are D,C, and B.

**Biology**

I would like some help if that is OK, like soon!:) 1.) A group of scientists proposes an idea that a chemical compound will enable bean plants to grow faster. They grow one group of bean plants in the presence of the compound and another group in the absence of the compound. ...

**AP Chemistry**

If the pH of a nitric acid solution is 2.34, then what is the molarity of nitric acid in the solution? A. 1.6 × 10-4 M B. 3.8 × 10-3 M C. 2.2 × 10-2 M D. 4.6 × 10-3 M

**AP Chemistry**

What should be the range for the exponent of [H+] in solutions that are characterized as acidic? A. 0 to -0.07 B. 0 to 0.7 C. 0 to -7 D. 0 to 7

**ap chemistry**

What is the [H3O+] of a solution with [OH-] = 6.3 × 10-4 M? A. 6.3 × 10-18 M B. 10.80 M C. 6.3 × 10-4 M D. 1.6 × 10-11 M DrBob222 can you help me with this question please?

**Government**

And I just took it, and B is correct.

**Algebra**

Sally bought 12 tickets for a movie, an adult ticket costs $9 and a child ticket costs $5, if she spent a total of $76, how many adults and children did she buy tickets for?

**Math**

0.41,0.46, 0.6

**algebra**

for what value of x is the rational expression below equal to zero? 2-x/2+x

**maths**

solve the system of equations algebraically for real values of x and y { x+u=16 x^2 +y^2 =128

**calculus**

find the inverse of the matrix. [ 16 1 ] 1 16

**calculus**

Find the product [ 3 8 ] [ 4 5 ] 6 3 4 4

**calculus**

Find A - B A = [ 3 7 8 ] 7 9 3 7 9 9 B = [ 2 2 6 ] 6 7 8 5 8 6

**math**

if a patient walked 1/4 mile sun, 1/3 mile mon, 1/2mile tues, 7/12 mile wed, 3/4 mile thurs, 5/6 mile fri, and 1 fll mile sat, how many miles did the patient walk in a week?

**Social Studies**

Yea, Fred's answers are correct.

**Social Studies**

2 3 4 5

**Math**

Find an A.P. such that the sum of the first three terms is one half the sum of the next four terms, the first term being 12.

**Chemistry**

Determine the cell potential from the following half cells: Pb^o/Pb2+ and ZN^O/Zn2+ whre [Pb2+]=.86Mand [Zn2+]=0.35M Calculate K for this reaction. How long in hours would you have to let it go until you lower the voltage to 95 percent of the E from the Nernst equation at 7.2?

**pre cal**

The vector u = 94300, 5200) gives the number of units of two models of laptops produced by a company. The vector v = (1800, 1200) gives the price in dollars of the two models of laptops, respectively. Identify the vector operation used to increase revenue by 5%

**Pre Calculus**

The number of new accounts opened at a credit union in the years 2001 to 2006 can be approximated by the model N(t)= -80.6t^2+2100t+12000, where 11 <= t <= 16, with t = 11 corresponding to 2001. Using this model and your graphing calculator, determine the year in which ...

**Math**

Let R be the region bounded by y = ln x, x-axis, and x = 3. Answer the following. a) Write, but do not solve, an integral expression that will find the volume of the solid that results from rotating R about x = -2. b) Write, but do not solve, an integral expression that will ...

**Calculus**

Thank you so much!

**Calculus**

The base of a solid is the region bounded by the lines y = 5x, y = 10, and x = 0. Answer the following. a) Find the volume if the solid has cross sections perpendicular to the y-axis that are semicircles. b) Find the volume if the solid has cross sections perpendicular to the ...

**Just a random question that I'm interested in.**

All right, thanks!

**Just a random question that I'm interested in.**

Do Kayan women enjoy wearing the neck rings? From Kayan.

**Math**

An object moves along the path x^2 - y^2 = 5. At the point (-3, 2),dx/dt = -4. Find dy/dt at that same point. I understand that dy/dt of the function is y' = x/y but I am not sure how to find it at that specific point. Could you please help? Thank you!

**College Intro To Geography**

Discuss the ways in which geographers employ the ideas of distance, accessibility, and connectivity to describe the process of spatial interaction. The spatial interaction would be how people, or even animals, interact with each other. For instance how well do we connect with ...

**English**

The title "another evening at the club" is close in meaning to "just another evening at the club" given the events of the story, what is the significance of this meaning? I need help explaining this. I have no idea how to word it

**CHEMISTRY**

If you used only photons that were dropping from the n = 6 shell to the n = 1, how many of these photons would be required to keep a 100 Watt light bulb lit for 10 minutes?

**Chemistry**

how do I convert 5E-26 to Meters 60mph is 26.8224m/s I am having trouble in how to write it out (9.109E-31kg)(26.8223) or am I dividing the 5E-26 from the 26.8224?

**Chemistry**

If you were told that a ball had a wavelength of 5 x 10-26 nm at a velocity of 60 mph, what would be the mass of that ball in pounds?

**Math**

A fair coin is flipped four times. What is the probability that tails occurs exactly 3 times if it is known that tails occurs at least twice?

**Science**

Shale often contains fossils of leaves. Question: If the gastropods listed in line 3 and line 6 were collected from shale containing leaf fossils what would their possible age be? Question: Could you use radiocarbon dating to assign a numerical date/age to this rock unit? ...

**Science**

I'm doing research but I can still not find it.

**Science**

what the definition of age range in earth science?

**Science**

okay, and how about this question. Why Devonian could not be considered an index fossils?

**Science**

how? why?

**Science**

I still don't understand.

**Science**

The text above^^ is for this question: How can the occurrence of fossils and their known age ranges be used to date rocks?

**Science**

Fossil Occurrence and the Age of Rocks: Groups of fossil organisms occur throughout the geologic record for specific intervals of time. This time interval is called the fossil’s range. Knowing the range of the fossils of specific organisms or groups of organisms can be ...

**Science**

Why Devonian could not be considered an index fossils? How can the occurrence of fossils and their known age ranges be used to date rocks? Need help by understanding the question.

**Science**

I don’t understand the question, help?

**Science**

How can the occurrence of fossils and their known age ranges be used to date rocks?

**Math ~ CHECK ANSWER**

Below are two sets of student quiz scores on a 30-point quiz. Which of the following can you conclude by comparing their box-and-whisker plots? Class A: 5, 10, 13, 18, 19, 25, 29 Class B: 1, 3, 5, 7, 9, 9, 13 a) The first quartile of class B is greater than the third quartile ...

**chemistry**

In a certain experiment, the rate constant, k, was measured as a function of the temperature, T. Two data points were as follows: (A) 25°C, 1.1 x 10–5 min–1, and (B) 225°C, 2.4 x 10-2 min–1. The student who performed the experiment then ...

**Chemistry**

At 425°C, a reaction has a rate constant of 7.7 x 10–4 s–1 and has an activation energy of 275 kJ mol–1. What is the frequency factor? The answer is 2.9 x 1017 s–1 , I need help with working out I used arrhenius equation and rearranged ...

**Geometry**

Which is the equation of a 20 cm diameter circle with its center at (3, -6)? (x+3)^2+(y-6)^2=100 (x-3)^2+(y+6)^2=400 (x-3)^2+(y+6)^2=100 <my choice (x+3)^2+(y-6)^2=400

**Math**

Suppose f (0) = 9, f ′(0) = 2, and f ″(0) = -4. If df is used to approximate Δf when Δx = 0.01, which of the following would be true? df < Δf df > Δf df = Δf

**Math**

Thank you so much!

**Math**

A rectangle is bounded by the x-axis, the y-axis, and the line y = (4-x)/4. Find the maximum area of such a rectangle.

**Math**

Suppose f (x) = x^3 + x and g(x) = f^-1(x). Find g'(2). I am confused about how to find the inverse of f because I can't isolate y. Could you please help? Thanks!

**physics**

In a marathon race, Chad is out in front, running due north at a speed of 3.92 m/s. John is 94 m behind him, running due north at a speed of 4.33 m/s. How long does it take for John to pass Chad

**math**

Eufj j reh g d

**Math**

OK I don't know where to start 4 (2/4) × 4

**Math**

#1) 8/10 +1/3 = 34/30= 1 (4/30) Is my answer OK #2) 2/5 ÷1/3= 6/5 = 1 (1/5) Is my answer OK #3) 2/5 ÷ 1/3 =6/5= 1 (1/5) Is my answer correct

**Math**

#1) which digit is 10 times the value in the underline digit in 36,119,432 (#that is underline is number 1 between the 1 and 9 ) I think the answer is one hundred thousand #2) which digit is 1/1000 of the value in the underline digit in 19,832,456 (# underline is 3) My answer ...

**Math**

#1) Luis stated that when you are converting meters to centimeters your answer will be larger than your original number. My answer is yes because centimeters are smaller . (Is my answer OK ) #2) 8/9 + 1/3= 33/27= 1(12/27)= (I'm stuck here) #3) 6/8-2/6=2 (18/20) =2 (9/10) ...

**math**

I get 39.85

**History**

The political order of the 19th century, at the time combined people of many nationalities who wanted their own governments.

**History**

single most powerful European political ideology of the 19th and early 20th centuries political outlook, nationalism was and is based on the relatively modern concept that a nation is composed of people who are joined together by the bonds of common language as well as common ...

**History**

How did nationalism threaten the existing political order of the nineteenth century?

**Geometry**

Two similar triangles have a scale factor of 3 : 5. The altitude of the larger triangle is 24 inches. What is the altitude of the smaller triangle?

**geometry**

Questions 1 and 2 are wrong. 1. is triangular pyramid the other one is 2. is solid

**Physics**

A model rocket is launced from the ground with an initial velocity of 65 m/s directly upwards. If a horizontal wind is blowing at 5 m/s during the flight, how far from the launch point will the rocket land? I know I should probably be using the equation x=x0+v0t+1/2at^2, but i...

**math**

Nevermind. I figured it out. Key was 1 ppm is 1mg/L. 1.15 mg/L * 100,000 L = 115,000 mg (115g)

**math**

How many gram of sodium fluoride should be added to 100000 liter of drinking water containing 0.6 ppm of sodium fluoride to provide a recommended concentration of 1.75 ppm? Answer is 115 grams. I keep getting .115 g What am I doing wrong? Please help.

**Chemistry**

If 27 grams of propane react with 88 grams of oxygen to make carbon dioxide and water then how many grams of carbon dioxide can be made?