# Posts by sarah

Total # Posts: 5,778

**Calculus (trig derivatives)**

A lighthouse 2 miles offshore has a light that rotates once every 20 seconds. At what rate is the light traveling along the shore if it is shining on a point 4 miles along the shore from the point nearest the lighthouse?

**chemistry**

To determine the molecular weight of a liquid compound,1.56 grams of the compound is vaporized in a 0.555L container at 30ºC and the pressure is measured as 1.2 atm. What is the molecular weight of the compound?

**chemistry**

Question 16 options: A mixture of equal moles of He and Xe are in a plastic container at 25ºC and 874 mm pressure. If only He leaks from the container and the pressure decreases to 600 mm at 25º C, what is the mole fraction of (1) He and (2) Xe in the container after...

**Chemistry**

KClO3 decomposes according to the reaction below. How many grams of KClO3 are needed to produce 826ml of O2 at standard temperature and pressure? 2KClO3 ? 2KCl + 3O2

**Math**

I'm not sure if this is right but this is what I have so far 2cos^2 +sinx -1 =0 2cos ^2 x+sinx =1 (I added 1 to both sides) Cos^2 x +sinx

**Math**

Solve equation for 0< Equality x < 2pi Trig equations

**Math**

Please Help Solve each equation for 0<x<2 pi 2cos^ 2 x +sins-1=0

**Math**

Suppose k is a continuous function so that k(-2)=3 and k'(-2)= -4 . a. Use the given information to approximate the value of k(-1.4). b. If k''(x)<0 for -3<=x<=0 , will the approximation for k(-1.4) you found in part (a) be greater than or less than the ...

**Chemistry**

Thank you so much!

**Chemistry**

I am completely lost with this question. If 50 ml of 0.5M HCl is added to 800 ml of pure water, what will be the approximate pH of the resulting solution?

**Precal **

Cot^2x-csc^2x Please help me simplify using identities! Thank You!

**Precal **

Sin^2x/cosx =tanxsinx I need help in verifying also please tell me what identity u started with thank you!

**precal**

using trig identities and I need to verify please help

**precal**

(sin x + cos x)^2 tan x = tan x + 2 sin^2 x please help me verify the identity

**Biology**

The p53 enzyme system prevents progression to which stage of the cell cycle? choices are: 1. G1 2.Cytokineses 3.S phase 4. Mitosis 5. G2 * I think it's S phase, It's not G1 right?

**Trig Identities **

secx - sinxtanx

**Calc. Based Physics **

10.1 Three uniform spheres with masses m1 = 6.0 kg, m2 = 2.0 kg , and m3 = 4.0 kg are fixed at the positions shown in the diagram. Assume they are completely isolated and there are no other masses nearby. m_1 | | 3cm | m_2-- P ^ | 1cm |2cm m_3 (a) What is the magnitude of the ...

**World History **

Choose four of the following questions to ask Moses, Jesus, and Muhammad:? Ok I choose the questions and I got the first and third one I just need help with the second and forth question •Why is the Holy Land an important site for your faith? Moses: The book of my people ...

**Math**

Assume the carrying capacity of the earth is 9 billion. Use the 1960s peak annual growth rate of 2.1?% and population of 3 billion to predict the base growth rate and current growth rate with a logistic model. Assume a current population of 6.8 billion. How does the predicted ...

**Science **

What are some ways (at least two) that cells can increase their (Unicellular and multi-cellular organisms) surface area to volume ratio without splitting into multiple cells? One way that cells can increase their surface area to volume ratio without splitting into ...

**Science please help**

What are some ways (at least two) that cells can increase their (Unicellular and multi-cellular organisms) surface area to volume ratio without splitting into multiple cells? One way that cells can increase their surface area to volume ratio without splitting into multiple ...

**Math1**

Since the bacteria is doubling every hour, it won't be multiplying by 2. So 24 times 2 won't be the formula. Instead you would square it. doubles so 2^24.

**science**

What are some ways (at least two) that cells can increase their (Unicellular and multi-cellular organisms) surface area to volume ratio without splitting into multiple cells? I am having trouble finding information on the ways.

**LESSON 12 Social Studies 8 B Unit 3: Reconstructi**

I'm stuck on the same question is the answer A?

**Science **

For this activity, we had to make cube shaped models to represent cells. Then we had to compare surface area, volume, and surface area to volume ratio (SA:V) between the cells. Cell A: length of one side=1cm Surface area= 6cm^2 Volume= 1cm^3 SA:V...

**Algebra**

Yup that's correct, 336

**Math**

Find the change in mass. So difference of 54 and 48 is 54-48 = 6 Now the original mass is 48 so you would divide 6/48 = 0.125×100=12.5 Your answer should be 12.5% I'm pretty sure

**science**

For this activity, we had to make cube shaped models to represent cells. Then we had to compare aurafve area, volume, and surface area to volume ratio (SA:V) between the cells. Cell A: length of one side=1cm Surface area= 6cm^2 Volume= 1cm^3 SA:V= 6 Cell B: Length of one side...

**Calculus**

If ln(x^2-15y)=x-5+5 and y(-4)=1 find Y prime(-4) by implicit differentiation thus the equation of the tangent line to the graph at the point (-4,1) is y=

**math help**

Ms.sue may you help me? A user named Cory is keep on bothering me. Every time I post this question, Cory harasses by saying they know the answer and they aren't going to tell me. I need help with this issue and also with this math problem. Thank you for your time and effort

**math help**

Given f(x)=7-2x find f (x+5) I'm not sure how to approach this problem. I have done this so far: F(x+5) = 7-2x F(x+5)=7-2(x+5) F(x+5)=7-(2x+10) Not sure if this is right and what to do next.

**math**

Oh. Thank you so much! I am glad that you helped.

**math**

Given f(x)=7-2x find f (x+5) I'm not sure how to approach this problem. I have done this so far: F(x+5) = 7-2x F(x+5)=7-2(x+5) F(x+5)=7-(2x+10) Not sure if this is right and what to do next.

**math**

I've been trying to solve it for a ay already and decided to ask on here. May I please get help on how to do this? It'll be great and I'll appreciate if you could help.

**math**

Given f(x)=7-2x find f (x+5) I'm not sure how to approach this problem. I have done this so far: F(x+5) = 7-2x F(x+5)=7-2(x+5) F(x+5)=7-(2x+10) Not sure if this is right and what to do next.

**Chemistry**

Determine the pH of a solution after 20.00 mL of 0.4963 M HI has been titrated with 12.64 mL of 0.5174 M NaOH.

**Chemistry**

Consider the titration of 20.00 mL of 0.1728 M Ascorbic acid (Ka = 7.9 x 10-5) with 0.4329 M NaOH. Match the following regions in the titration curve with the appropriate pH range. 1.Initial pH 2.Before equivalence point 3.At equivalence point 4.After equivalence point A. 8 - ...

**Chemistry**

Determine the pH of a solution after 20.00 mL of 0.4963 M HI has been titrated with 12.64 mL of 0.5174 M NaOH.

**OChem**

Suppose a student obtained a 0.15g of cruse salicylic acid. How much water would be needed to just dissolve it at 75 degrees Celsius? How much salicylic acid would remain dissolved in that amount of water at just 10 degrees Celsius? What percent of the original mass of the ...

**English**

Should animals be tested for science research

**English**

that* instead of at

**English**

All things considered, it seems reasonable that injecting a small dosage of drugs in animals is acceptable. This practice could help to find cures for the illnesses as well as animals. Having said that people are not acknowledging the positive results of these trials. Another ...

**English**

It's for my argumentative essay

**English**

I'm not against it...

**English**

what percentage of animal testing is successful

**English**

Thanks

**English**

All things considered, it seems reasonable to that injecting a small dosage of drugs in animals is acceptable. This practice could help to find cures for the illnesses. Like so?

**English**

What do u mean by put a period after acceptable?

**English**

All things considered, it seems reasonable to that injecting a small dosage of drugs in animals is acceptable as this practice could help to find cures for the illnesses

**English**

I don't get it...

**English**

All things considered, it seems reasonable to accept that injecting a small dosage of drugs in animals is acceptable as it could help and improve to find cures for the illnesses. How can I improve? what words shall I remove?

**English**

All things considered, it seems reasonable to accept that injecting a small dosage of drugs in animals as it could help and improve of find cures for the help

**English **

How can I rewrite this sentence using parallel structure? The stirring closing paragraph is the formal pronouncement of independence and borrowed from the resolution of independence adopted by congress July 2, 1776.

**Biology**

A biologist found that 20% of a population of bats are brown, which is recessive. assuming the population shows Hardy-Weinberg equilibrium, determine the genotype and the allele frequencies of the population?

**Math**

Tan 57= f/70 f= 70tan 57 =107.79 tan 59 =(f+t)/70 f+t= 70 tan 69 =182.356 t=70 tan 69- f =70 tan 69 - 70tan 57 = 74.5m

**Physics**

The femoral artery carries blood to the leg and has a diameter of 12.5 mm. What is the resistance in a column of blood that is 2.20 cm long if the conductivity of blood is 0.630 ?-1m-1?

**Math**

A Gallup poll asked two questions: 1. Do you favor a tax cut or “increased spending on other government programs”? Result: 75% favored a tax cut. 2. Do you favor a tax cut or “spending to fund new retirement savings accounts, as well as increased spending on ...

**math**

Simplify the expression 23w^3-5w^2x+8wx^2-8w^3-13wx^2+30w^2x Group like terms so: 23w^3-8w^3= 15w^3 -5w^2x+30w^2x= 25w^2x 8wx^2-13wx^2 = -5wx^2 The final answer I got is: 15w^3+25w^2x-5wx^25wx Is this right? I had to simplify the expression.

**Chemistry**

When 0.010 moles of Zn(s) reacts with 30.0 mL of 1.0 M HCl, the H2 gas produced is collected in a 1.0 L flask at a temperature of 270 K. What is the pressure (atm) of H2 gas collected? Zn(s) + 2HCl(aq) = ZnCl2(aq) + H2(g)

**Chemistry**

When 0.010 moles of Zn(s) reacts with 30.0 mL of 1.0 M HCl, the H2 gas produced is collected in a 1.0 L flask at a temperature of 270 K. What is the pressure (atm) of H2 gas collected? Zn(s) + 2HCl(aq) = ZnCl2(aq) + H2(g)

**Physics**

An object is given two initial velocities, one that has a magnitude of 60.0 ms-1 and points along a direction that is 35.0° north of east and the other has a magnitude of 55.0 ms-1 that points 15.0°, also north of east. Determine the resultant velocity of the object.

**Physics**

A plane travels 3 km due north, then 5 km due northeast. Represent these two displacements graphically and determine the resultant displacement by finding is magnitude and direction.

**Chemistry**

2AgNO3(aq) + K2CrO4(aq) ==> Ag2CrO4(s) + 2KNO3(aq) Ag2CrO4(s) ===> 2Ag^+ CrO4^^2- Ksp = [Ag^+]^2[CrO4^2-] Ksp = (2x)^2(0.1)

**Chemistry**

Calculate the mass of solid AgNo3 that can be added to 2.0 L of 0.10M K2CrO4 solution in order to just start precipitation?

**calculus**

find y' if x^2y^4+3y-4x^3=5cos x-1 (2x*y^4)+dy/dx 4y^3*x^2)+dy/dx3+12x^2=5-sin-0 dy/dx=-5sin (x -12 x^2)/(2x*4y^3)+(12y^2+x^2) this is using implicit differenation is this correct

**calculus**

find y' if x^2y^4+3y-4x^3=5 cos x-1 (2x-y^4)+(dy/dx4y^3*x^) +dy/dx+12x^2=5(-sin x-1) is this started correctly

**Physics**

sorry, I forgot to inlcude the mass and the angle given. The mass is 10 kg and the angle is 45 degrees

**Physics**

The box is being pulled by a roope across a level floor as shown in the diagram. The box is accelerating at 1 m/s2, the coefficient of kinetic friction is 0.5. what is th tension in the rope?

**Physics**

mg sin theta - F = ma (9.8 sin 30) - 2 / (9.8 cos 30) = 0.34

**Physics**

you are skiing down a slope angled at 30 degrees to the horizontal. Your acceleration is 2m/s^2. what is the coefficient of kinetic friction between you and the hill?

**math**

Oh okay. So since there is a adding or subtracting sign with brackets, all you do is collect like terms? Okay. So it is not distributive property

**math**

Simplify (5x+3)+(8x+1) (5x)+(8x)= 13x^2 (5x)+(1)=5x (3)+(8x)=11x (3)+(1)=4 =13x^2+5x+11x+4 =13x^2+16x+4 Is this right or wrong? Simplify (2t^2-3t)-(7t^2-5t) = (2t^2)-(7t^2)=-5t = (2t^2)-(-5t)= 7t =(-3t)-(7t^2)=-...

**math**

(2t^2-3t)-(7t^2-5t) = (2t^2)-(7t^2)=-5t = (2t^2)-(-5t)= 7t =(-3t)-(7t^2)=-10t =(-3t)-(-5t)=2t =-5t+7t-10t+2t I am confused. Why are all my answers "t" and none of them are "t^2"?

**math**

Simplify (5x+3)+(8x+1) (5x)+(8x)= 13x^2 (5x)+(1)=5x (3)+(8x)=11x (3)+(1)=4 =13x^2+5x+11x+4 =13x^2+16x+4 Is this right or wrong?

**Math**

A toy store has found that 30% of its customers spend more than $40 each visit. What is the probability that the next two customers will each spend more than $40?

**physics**

& this one... 4. A person drops 740 g rock originally held 6.5 ft above the ground. What is its velocity the moment before it hits the gound. (Assume rock doesn't gain/lose energy)... (Hint: You will need to calculate the P.E of the rock before it's dropped!

**physics**

Last one! Thankyou for the help thus far... calculate the KE in kJ of 9.100 x 10^5 atoms of silver moving at 1800. km/hr. ... the atoms part is what I'm confused about.

**physics**

I'm not sure with this conversion... getting 9.843x10^4 ft/min to m/s ? How do I get to m/s using a specification conversion without using online conversions?

**Physics!**

stuck on this one!

**Physics**

calculate K.E in Joules of a baseball w/ a mass of 237.2 cg moving at 85.00 mph

**Physics**

The dipole moment of a water molecule is 6.37E-30 Cm. What is the electric potential's magnitude 1.58 nm from a water molecule along the axis of the dipole?

**Math**

Can I please see your solution?Thanks!

**science**

What can people do to reduce global warming?

**science**

what causes clouds to form?

**Chemistry**

Which of the following statements cannot be assumed for the vapourization of a liquid? A)Enthalpy is positive B)Entropy is postive C)Temperature (in degrees Celcius) is positive D)They are all true

**Chem**

Yes

**Chem**

Specify the concentration of each ion in solution for the following: .10 M AlCl3 (aq) and .15 M (NH4)2SO4 (aq)

**Chem**

21.7 mL of 1.15 M KOH (aq) was required to titrate 25 mL of H2SO4 (aq) as follows: H2SO4 (aq) + 2KOH (aq) --arrow-- K2SO4 (aq) + 2H2) (l) What is the molarity of the H2SO4 (aq)?

**Chem**

Add them all together and then divide by the number of dimes. Put your answer in the ones place.

**Physics**

a periscope is an optical instrument made of two plane mirrors inclined at an angle 45 with respect to the axis of the tube. an observer places her eye at point O. draw the path of a ray light issued from A. determine the position and the nature of the image of A given by two ...

**english 101**

yes you are right bc they had drove is wrong bc drove isnot pp

**english 101**

no they had drove make sounds better since its a past perfect ??am I right??tnx

**english 101**

hi guys I need a help in my grammer class?? After throwing their sleeping bags into the backseat of their cars they-- ((had drove/drove/drivig/having driving))--more than 400 miles to reach their destination. I think driving is right.??

**Spanish 202**

I have some answers for my spanish class. I was hoping the grammar could be checked. Antes de estudiar esponal había dormido. Con $100000 compraría una mona. Mi passión ideal sería bombero. Comería muy mucha comida todo día. Si no ...

**Chemistry**

You start with 2.5L of a KNO3 stock solution and wish to prepare 10.0 L of 1.5 M KNO3. What percentage (m/v) would the potassium nitrate stock solution need to be if you were to use it all? (MW of KNO3: 101g/mole)

**Chemistry**

Consider a one step reaction. Which of the following does not describe the activation energy of the process? The minimum amount of energy needed for a reaction to occur The energy difference between the starting point and the transition state The energy required to distort or ...

**Chemistry**

Benzene (C6H6) has a normal freezing point of 5.50oC and a density of 0.88 g/mL. When 1.28 g of naphthalene (C10H8) is dissolved in 125 mL of benzene, the freezing point of the solution is 5.03oC. Determine the molal freezing point constant for this solvent.

**Chemistry**

Consider a one step reaction. Which of the following does not describe the activation energy of the process? The minimum amount of energy needed for a reaction to occur The energy difference between the starting point and the transition state The energy required to distort or ...

**math**

.20x+x=? what is ?

**Physics**

Which is the best example of Newton's Third Law of Motion? A hockey puck sliding on the ice will keep going until it is hit by another player or hits the wall. It takes more force to move a large tractor trailer than it does to move a small sports car. A swimmer who jumps ...