# Posts by Sarah

Total # Posts: 5,778

**Biology**

I forgot to mention that the volume of the amalyse stock is 50 ug/ml. and 2.5ml amylase stock and 2.5 ml buffer.......so i think I should take: 50ug/ml/5.0 ml = 10 The the dilution factor is 10x Is this correct do you think?

**Biology**

If I have 2.5 amylase stock solution, 2.5 PBS Buffer, and final amylase concentration of 25 [ug/ml] , how do you calculate the amylase dilution factor?

**calculus**

limx--->0 3sin 3x/4x would it be 9/4

**calculus**

limx-->3 sin 3x/4x

**Physics **

A baseball is thrown at 40 m/s. Jose Bautista hit it back in the opposite direction at a speed of 65 m/s. The ball is in contact for 1.2 ms. What distance does the ball travel while it is in contact with the bat?

**Math**

f(x+h)?f(x)=8hx^2+2hx+2h^2x?3h^2?4h^3. Find f?(x).

**MATH @Damon @ms. Sue**

Belinda wants to invest $1000. The table below shows the value of her investment under two different options for three different years: Number of years 1 2 3 Option 1 (amount in dollars) 1100 1210 1331 Option 2 (amount in dollars) 1100 1200 1300 Part A: What type of function, ...

**MATH @Damon @ms. Sue**

Part A:Option 1 is linear because it increased arithmetically by $110.00 a year. Option 2 is exponetial because it is increased geometrically by $1.09 a year Part B: Option 1 100x+1000 5.5x^2+93.5+1001 Option 2 100(20)+1000 2000+1000=300 Part C: After 20 years she would get $...

**MATH @Damon @ms. Sue**

Can Someone check my Work Belinda wants to invest $1000. The table below shows the value of her investment under two different options for three different years: Number of years 1 2 3 Option 1 (amount in dollars) 1100 1210 1331 Option 2 (amount in dollars) 1100 1200 1300 Part ...

**Physics**

let me try this again area formula is 1/2 x b x h 1/2 x 2.705 x 6.22 m/s = 8.4125 m is this correct? so after 11.7 seconds the particle position will be 8.4125 m?

**Physics**

I just saw related questions so I figured it out. (28.7/53.56)(sin 106) = 0.515 sin-1 0.515= 31.00deg 31.00deg -19deg = 12.00 deg

**Physics**

Two geological field teams are working in a remote area. A global positioning system (GPS) tracker at their base camp shows the location of the first team as 38 km away, 19deg north of west, and the second team as 28.7 km away, 35deg east of north. When the first team uses its...

**calculus**

I have a definition lim theta approaching 0 sin theta/theta = 1 so show if the limit x approaching 0 sin2x/5=2/5

**Physics**

A boy kicks a rock off a cliff with a speed of 15.5m/s at an angle of 53.5° above the horizontal. The rock hits the ground 5.37s after it was kicked. How high is the cliff? I found the height of the cliff which is 7.45*10^1 m. What is the speed of the rock right before it ...

**Chemistry**

The density of water at 60 degrees C is 0.98338 g/mL. What is the mass of 37.48 mL of water in a graduated cylinder (not including the mass of the graduated cylinder)

**Math**

It takes 3 mins to fill a tub to the top and five minutes to drain the full tub.if the faucet and drain are both open how long will it take to fill the tub

**MATH @Damon @ms. Sue**

Thank you so much Steve :)

**MATH @Damon @ms. Sue**

Given the function f(x) = 2(3)^x, Section A is from x = 0 to x = 1 and Section B is from x = 2 to x = 3. Part A: Find the average rate of change of each section. Part B: How many times greater is the average rate of change of Section B than Section A? Explain why one rate of ...

**Biology**

Explain the meanings of Mendel’s principle of segregation and principle of independent assortment. Under what circumstances does the principle of independent assortment hold true? Give an example in which this law does not apply.

**Pre calc**

Evaluate the expression given that cosine a=4/5 with 0<a<pi/2 and sin b=-15/17 with 3pi/2< b<2pi

**Calculus algebra review**

((1/2+h) -(1/2)) / h found LCD of numerator ((2)-(2+h)/2(2+h))/h is it 1

**Physics**

ok i got it, thanks. 4.10*10^5

**Physics**

An auditorium measures 43.0m × 18.0m × 15.0m. The density of air is 1.20 kg/m3. What is the volume of the room in cubic feet? (Do not input units. Note that 1m = 3.28ft) My Answer 43x18x15 = 11,610 m^3 11,610m3 * 3.28ft m = 38,080.8 ft When I used this number I got...

**math**

6. You are given a sheet of cardboard that is 8.0 in. x 11.0 in. How many full circles with a diameter of 3.0 inches can you cut from the cardboard? What is the percentage of waste if the

**social studies**

Thank you!

**social studies**

In America, citizens with voting rights can A. Make the laws. B. Vote for or against any law. C. Propose new laws. D. Vote for or against the officials who make the laws. <<<<< somebody please help me

**Stoichiometry **

Determine the mass % (m/m) of a NaCl solution if 58.5 grams of NaCl was dissolved in 50 ml of water (assume the density of water to be 1.0 g/ml).

**Mathematics**

F(x, y) represents a velocity field of a fluid over a surface S defined by z = 6 ? 3x ? 2y. If the magnitude of the velocity in the direction of the unit normal vector, n?, on S is 3z??14, compute the flux of F(x, y) over the surface S in the first octant oriented upward, ...

**Math**

a photocopier increase the sides of a square in a ratio of 5:4. what percentage has the size increased?

**English**

Either individuals chose to face their conflict, and fight for it in a positive manner. Or they can run away from their problems, and deal with them in a negative manner. Its MORE important for individuals to face their conflicts and fight for them. The way they choose to ...

**Chemistry**

Hi , I have this question and I do not know what steps to follow. Please help guide me. It will be really appreciated. Calculate the extent of oxidation in a stream where water it's in equilibrium with atmospheric oxygen and had a pH pic 6.5 (a(H3O+) =antilog (-6.5) ). The...

**Math**

Mr. Jones makes 3% commission on his sales of widgets. At a different company, Mr. Smith makes 5% commission selling the same widgets at the same price. Mr. Smith sold 500 fewer widgets than Mr. Jones, and they both earned the same commission. How many widgets ...

**Math**

If two pounds of meat will serve 5 people, how many pounds will be needed to serve 13 people?

**Math**

How do you find the constant rate of change?

**Math**

Under ideal? conditions, a population of rabbits has an exponential growth rate of 11.8?% per day. Consider an initial population of 300 rabbits. Find the exponential growth function.

**Chemistry**

Then if H+ equals antilog pH, M- would also be equal to H+ , so then what will I be solving for? Because H2M species is given Sorry if this is a stupid question, I really don't know Thanks you!!

**Chemistry**

Okay so my lecturer has this in our slides and there are no notes just a heading saying speaciation, I have tried google and everything I have read does not include pH in their question. Please help me Calculate the equilibrium concentrations of the different species in a 0....

**math**

Juan has three rain sticks measuring 8 inches, 6 inches, and 12 inches each. what is the least common multiple of 8, 6, and 12? A.12 B.24*** C.48 D.96 is it B?

**Calc**

If y=tanu, u=v-(1/v), and v=lnx. What is the value of dy/dx at x=e?

**Calc**

If x=t^3-t and y=?(3t+1), then dy/dx at t=1 is what?

**Calc**

If f(x)=6x^3-4x then d/dx(f(lnx)) would be what equation?

**Calc**

The tangent line to the graph of y=f(x) at both x=3 and x=4 is y=-x+5. Which of the following statements must be true? The function f(x) is the line y=-x+5 f(3)=f(4) f'(3)=f'(4) f(x) is not differentiable at x=3 and x=4 None of the above

**Chemistry**

What size volumetric flask do you need to dilute a 0.150M NaOH to 0.390M if you pipette 1500ml?

**science**

In The Darkest Part Of The Mansion, Where The Winds Are Set To High, A Man Fears His Presents, Where The Cotton Lies, Where Am I?

**Chemistry**

In Cl2 + 2KBr -> 2KCl and Br2 produce that brown yellow effect?

**Physics**

You are given five identical resistors each of resistance r. How can you arrange all these resistors (in series, in parallel, or both) in order to have an equivalent resistance of 7r/2, 7r/3 or 2r

**Statistics**

The heights of women in a certain population have a Normal distribution with mean 64 inches and standard deviation 3.5 inches. We select three women at random from this population. Assume that their heights are independent. Find the probability that the tallest of these three ...

**Dr.Bob Chemistry**

Is HOET associated with E1 or E2? I think it is E2.

**Chemistry**

Sample A: Solid appearance:crystals, solids, white Solid Conductivity:no Solubility: soluble Solution appearance:substance disappears slowly Solution Conductivity: yes Relative melting point:2nd Sample B: Solid appearance:brown, tiny solids, dirt appearance Solid Conductivity...

**Chemistry**

When you try to leave your room you learn that the only door out is locked. Assuming there is no air flow into the room (air tight with no ventilation system) how long can you survive in the room (5 meters long, 5 meters wide, 5 meters high) -Human tidal volume (volume of air ...

**urgent math**

That's what is difficult for me. I have trouble drawing the diagram. Otherwise I know how to solve these problems. I need help drawing diagrams of these word problems. Is there a way you can possibly teach me how to draw diagrams?

**urgent math**

Paul is standing on a 39 m high building. The angle of elevation to the top of a taller building is 47 degrees and the angle of depression to the bottom of the same building is 36 degrees. What is the height of the taller building to the nearest tenth.

**French**

Can someone who is fluent in french look over this and make sure it makes sense? Ma maison de rêve est à Paris. Il a le sous-sol, le rez-de-chaussée, et le premier étage. Il a la cuisine, la salle à manger, la salle de séjour, trois la ...

**English**

Choose the meaning of the bolded vocabulary word in each passage in the next six questions. I can't bold them so the word will be in caps. Check my answers * = My answer 1. "Once, the listener fancied that he could DISTINGUISH the accent of town's people of his ...

**Math**

Consider sequence Uvn=2x^2. Find (?u)vn and write u as an accumalation sequence

**Calc**

How do I find the indefinite integral of: sec(y)(tan(y) - sec(y)) dy

**Science**

D, does anyone here go to NCCA?

**Chemistry-Dr.Bob**

The specific rotation of pure enantiomer is known from the literature to be -20. The measured value of a solution containing A plus its enantiomer B (specific rotation must be +20) is -40. What is the ee (enantiomer excess) of this sample?

**Chemistry**

The specific rotation of pure enantiomer is known from the literature to be -20. The measured value of a solution containing A plus its enantiomer B (specific rotation must be +20) is -40. What is the ee (enantiomer excess) of this sample?

**math**

75,74,72,69,65.What is the pattern.

**Maths**

Theo had two-thirds of a box of chocolates left. He and his two sisters share the chocolate equally.What fraction of the whole box does each of them have? If the box had 54 chocolates , how many chocolate dose each person eat?

**oceanography**

14C has a half-life of 5,730 years. If we start with 70 grams of 14C at time zero how many grams of14C will be left after three half-lives?_________

**oceanography**

One (1) kilogram of seawater (35‰) contains __ grams of dissolved salts and grams of water?

**Calculus (AC)**

Steve, you've been an amazing help. Thank you so much. This is the last question I need checked. Solve ∜82 using differentials. I got 3.00926

**Calculus (answer check)**

The measurement of the radius of a circle is 16 inches, with a possible error of .25 inches. (Use differentials to approximate the possible propagated error and the percent error. Propagated error= 1.6% Percent error= 4.6%

**algebra**

You are buying two kinds of notebooks for school. A three-ring notebook costs $6, and a spiral notebook costs $3. You must have at least five notebooks. The cost of the notebooks can be no more than $24. Which system of inequalities, along x>0 and y>0 would you use to ...

**Math**

In a basketball game, Albert made 11 out of 15 free throws and Jake made 10 out of 13 free throws. Who had the greater ratio of free throws attempted? Explain your reasoning.

**physics**

How many joules of energy are required to heat 2 L of water from 25 C to 100 C? I looked up that the specific heat is 4200 J/kgK and i keep getting Q to equal 630000 but my homework website says that's wrong.

**Math**

Mary bought a scarf for five dollar spent Half of the remaining money on jogging shoes bought lunch for two dollars and then spent half of her remaining dollars on a DVD she had $10 left how much money does she start with?

**Math**

Mary bought a scarf for five dollar spent one and a half of her remaining money on jogging shoes bought lunch for two dollars and then spent half of her remaining money on a DVD she had $10 left how much money does she start with?

**maths**

annie bakes some cupcakes for her children. If she gives each child 8 cupcakes,she will have 2 cupcakes left.If she gives each child 9 cupcakes, she will need another 2 cupcakes. How many children does annie have? 8-2= 6 6 divide 2= 3 9-2= 8 8 x 3= 24 24 children.

**maths fraction**

1/2 of the pupils in a class are girls. 3/8 of the girls and 1/4 of the boys wear spectacles. what fraction of the pupils wear spectacles? 3/8 + 1/4 = 3/8 + 2/8= 5/8

**Math**

I have a question Me and a friend are doing our math homework and ran into a conflict What would be the product of 8-1x0+2/2 I say it would be 5 and my friend here says it would be 1 I did 1x0=0 8+2=10 10/2=5 Thanks

**chemistry**

draw the skeletal structure line-angle (line-bond) mode of 2-isopropyltoluene. Identify the number of hydrogen atoms bound to each carbon in the structure.

**History**

The answer was B!

**History**

What was the original purpose of the Bill of Rights? A) to give the people their natural rights B) to restrict the power of the national government C) to restrict the power of the national and state governments D) to give power to the national government I believe the answer ...

**American Government**

The correct answer was B. :)

**American Government**

American foreign aid might be used to support which of the following foreign policy? A) Deterrence B) Containment C) Collective Security D) Isolationism My guess is B or possibly C? Definitely not A or D.

**American Government**

Yes, I completely agree. I notified my teacher about the questions error so hopefully it'll be fixed soon. However, until then, I thought I'd state was the correct answer was (even though it was technically wrong) for other students who may go to my school. :)

**American Government**

The correct answer was Senate.

**American Government**

Sadly, my teacher is absent until the 10th. Thank you for your help anyway. :) Hopefully someone whose completed this lesson before will be able to help.

**American Government**

Who counts the Electoral College vote? A) House of Representatives B) Senate C) State legislatures D) Supreme Court My textbook says "The president of the Senate opens the electoral votes from each State and counts them before a joint session of Congress." I assume ...

**PROBABILITY MATH HELP!!!!! DICE**

A die is rolled. Find the probability of the given event. The number showing is an even number; The probability is :

**Sets & Probability math Help please**

A group of people were asked if they had run a red light in the last year. 206 responded "yes", and 184 responded "no". Find the probability that if a person is chosen at random, they have run a red light in the last year.

**PROBABILITY MATH HELP!!!!!**

Is letter c a 3?

**PROBABILITY MATH HELP!!!!!**

A die is rolled. Find the probability of the given event. (a) The number showing is a 5; The probability is? (b) The number showing is an even number; The probability is ? (c) The number showing is greater than 5; The probability is?

**Trig**

Cosine theta=8/17 and 270 degrees is < theta, and theta is< 360

**History**

My answer is C

**History**

Based on Common sense and the crisis what conclusion can be made about Thomas Paine? A : Thomas Paine accepted blame for causing the war B: Thomas Paine believed that colonist should remain loyal to the king C : Thomas Paine used his writing to persuade and inspire others. D...

**Physics**

We have a charge q = -0.6 x 10^-6 C at origin. And a vector r = (4 m, 3 m, 0 m). Find the electric field E(r) as a vector expressed in terms of i j and k. What is the distance in this case? Magnitude of r? Also, how do I find the Electric field as a vector? I'm stuck..

**math**

how do I order these from least to greatest: 1/2, -0.75, 0.6, -1/2

**Chemistry**

Aqueous solutions of copper (II) sulfate, CuSO4, and potassium carbonate, K2CO3, a blue parcipitate of copper (II) carbonate forms in addition to one other compound. We have to write the balanced chemical equation for that but our teacher didn't teach us anything about that

**Math , trigonometry**

From a point on the ground 20m from the base of a tree the angle of the elevation to the top of the tree is 47 degrees. Calculate the height the of the tree correct to the nearest metre ???

**bio**

1. Complete the following conversions: 1ul= what mal I thought 1000 100ul = what ml 50ml = what ml ul=1.5 ul=0.06ml ul=0.003ml idk how to do this was not in lab

**Math**

Solve for x 4(log(x)+5)=6

**Math**

Solve for p 93=12(2)^p

**chem**

If you were asked to convert 25 cg to the unit hg, which of the following would be the first fraction used in the conversion? 1 hg/10^2 10^2/1hg 10^2 hg/ 1cg 10^-2 g/1 cg

**calculus and chemistry**

Thank you so much I realized I was missing the -5 at the end

**calculus and chemistry**

A container of hot liquid is placed in a freezer that is kept at a constant temperature of 10°F. The initial temperature of the liquid is 160°F. After 5 minutes, the liquid's temperature is 60°F. How much longer will it take for its temperature to decrease to ...

**calculus**

A container of hot liquid is placed in a freezer that is kept at a constant temperature of 10°F. The initial temperature of the liquid is 160°F. After 5 minutes, the liquid's temperature is 60°F. How much longer will it take for its temperature to decrease to ...