Thursday
April 24, 2014

Posts by Rachel


Total # Posts: 1,164

Physics
You are hiking out in California and come across an abandoned mine shaft. Wondering how deep the mine shaft is you toss a rock in and it takes 5.1 seconds before hitting the bottom. How deep is the mine shaft in meters?

Finite Math
Assume that you randomly select 8 cards from a deck of 52. What is the probability that all of the cards selected are hearts?

Geometry
Two sides of a rhombus form a 120º angle. The length of each side is 6 in. Explain how to find the area of the rhombus, and then calculate the area. Leave your answer in simplest radical form.

Geometry
Two sides of a rhombus form a 120º angle. The length of each side is 6 in. Explain how to find the area of the rhombus, and then calculate the area. Leave your answer in simplest radical form.

Geometry
The lengths of three sides of a triangle are given. Describe each triangle as acute. right. or obtuse. 5, 6,10.

geometry
The lengths of three sides of a triangle are given. Describe each triangle as acute. right. or obtuse. square root 5, 3, square root 14.

chemistry
how do i find polyatomic ions?

Chemistry
Why do metals tend to be malleable?

history
That answer is not correct.

physics
A skier is pulled up a slope at a constant velocity by a tow bar. The slope is inclined at 25.9° with respect to the horizontal. The force applied to the skier by the tow bar is parallel to the slope. The skier's mass is 55.3 kg, and the coefficient of kinetic friction...

physics
The initial velocity of a 2.56 kg block sliding down a frictionless inclined plane is found to be 1.13 m/s. Then 1.08 s later, it has a velocity of 3.99 m/s.What is the angle of the plane with respect to the horizontal?

physics
Two blocks of mass m = 14.9 kg each are fastened to the ceiling of an elevator,The elevator accelerates upward at a = 1.62 m/s2. Find the tension in the bottom rope and the top of the rope.

physics
An elevator (cabin mass 540 kg) is designed for a maximum load of 3500 kg, and to reach a velocity of 4 m/s in 3 s. For this scenario, what is the tension the elevator rope has to withstand?

physics
A 3.24 kg block located on a horizontal frictionless floor is pulled by a cord that exerts a force F=11.8N at an angle theta=23.0degrees above the horizontal, as shown. What is the magnitude of the acceleration of the block when the force is applied? b.) What is the horizontal...

physics
A 3.24 kg block located on a horizontal frictionless floor is pulled by a cord that exerts a force F=11.8N at an angle theta=23.0degrees above the horizontal, as shown. What is the magnitude of the acceleration of the block when the force is applied?

physics
A professor drives off with his car (mass 840 kg), but forgot to take his coffee mug (mass 0.37 kg) off the roof. The coefficient of static friction between the mug and the roof is 0.7, and the coefficient of kinetic friction is 0.4. What is the maximum acceleration of the car...

physics
A professor drives off with his car (mass 840 kg), but forgot to take his coffee mug (mass 0.37 kg) off the roof. The coefficient of static friction between the mug and the roof is 0.7, and the coefficient of kinetic friction is 0.4. What is the maximum acceleration of the car...

physics
An object glides on a horizontal tabletop with a coefficient of kinetic friction of 0.65. If it comes to rest after 0.9 seconds, what was its initial velocity?

physics
An object glides on a horizontal tabletop with a coefficient of kinetic friction of 0.55. If its initial velocity is 4.1 m/s, how long does it take for the object to come to rest?

math
Factor the given expression. a) 6y^2 − 53y − 9 b) Set the expression equal to zero and solve for y. y= (smaller value) y= (larger value)

Honors Algebra 3-4
can the cubed root of 15x^2, over 3 be simplified any more. (original problem: cubed root of 5/3x) the directions were to rationalize the denominator of each expression. Thankss!!!!!

Algebra 1
Find the greatest common factor of 12x^2+18x-36

physics
At 1:00 p.m. a car, traveling at a constant velocity of 98 km/h toward the west, is 19 km to the west of our school. How far from the school will it be at 3:30

Chemistry
Determine the volumes of 1 M acetic acid and 1 M NaOH required to make a 200mL 0.1 M buffer with a pH of 5.5. (Assume the pKa of acetic acid is 4.76).

algebra
Including a 9% sales tax, an inn charges $127.53 per night. Find the inns nightly cost before tax is added

algebra
Club A offers a starter fee for $17 plus a monthly fee of $11. Club B offers a starter fee of $23 and a monthly fee of $14. How many months untill the prices will be the same?

math
f:(x)= x^2+5 find f(0)

trig
evaluate sin (11pi/6) to the nearest thousandth.

math
a+4(6a+2b^2)+(a^2-6b^2)

algebra 1
Maria sells paintings in an art gallery. She ears $375 each week plus a commission equal to 2.5% of her sales. This week her goal is to earn at least $500. What is the minimum amount of sales she must have this week to achieve her goal?

Physics
is it possible to solve without the initial temperature of the copper?

Physics
A 500 g glass beaker is in thermal equilibrium with 100 ml of 20 Degrees celsius water in it. If a 5 g sample of copper is placed into the water and the system is allowed to come into thermal equilibrium, what will the final temperature of the system be? (assuming no heat loss...

Chemistry
5 - got it

Chemistry
How would you make an irreversible isothermal expansion/compression cycle of a gas closer to a reversible one? 1. Increase the temperature 2. Decrease the number of steps during expansion and compression 3. Increase the difference between internal and external pressures 4. Dec...

algebra 1
Which expression is the greatest common factor of (125t^3 m^5+60t^4 m^4+85t^5 m^2)

Science
pressure=100N/20M/S

algebra 1
16

algebra 1
Evaluate: 2m^2-(n-p) when m=3, n=-2, p=-4

chemistry
Okay this makes sense thank you!

chemistry
What mass of barium sulphate can be produced when 100.0 mL of a 0.100 M solution of barium chloride is mixed with 100.0 mL of a 0.100 M solution of iron (III) sulphate? Please explain!

present annuity
What is the present value of an annuity that consists of 28 monthly payments of $260 at an interest rate of 8% per year, compounded monthly? (Round your answer to the nearest cent).

algebra 1
There are 16 coins in a piggy bank. The coins are all nickels and dimes. All together the total amount of money in the bank is $1.05. How many of each coin are there?

Geometry
Line AB (0,0) is perpendicular to line BN (3,4) in the diagram at the right. Angle B is a 90 degree angle. What are the coordinates of point N?

3rd grade math
No the answer is 36. Try plugging it into the problem. 36 divided by 2 is 18, which is 6 times 3. Then if you add (the opposite of subtracting) 3 groups of 3 (nine) from 3 multiplied by nine (27) you get 36

3rd grade math
Well first 3 x 6= 18 so multiplied by two to get your answer 18x2=36 to check use the second part of the problem: 3x9=27 36-27=9 subtract three groups of three (9) 9-9=0 so we have the correct answer

chemistry
Sorry, but how did you find the total volume of the solution?

chemistry
Thank you so much, I really appreciate your help!

chemistry
Aqueous silver nitrate reacts with aqeous potassium iodide in a double-replacement reaction to produce a precipitate of silver iodide. If 34.6 ml of 0.563 M silver nitrate are used with 148.4 ml of potassium iodide: a) What molarity of potassium iodide will be needed to consum...

algebra 1
Is it right?

algebra 1
i actually wrote the second part wrong. Its supposed to be y=.8x+7.2 not 72. and when i solved it i got 10.4 for y and my x is 4.

algebra 1
Solve by substitution. y=.8x+72 20x+32y=48 How do you get y? i got the x part but i can't seem to get the y part.

Astronomy-HELP PLEASE!!!!!
Some quasars (quasi-stellar radio source) have the largest red shifts ever observed. If this phenomenon is due to cosmic expansion, what can you say about their distance? What can you say about the age of the quasar at the time the light we now see left the quasar compared to ...

ASTRONOMY-HELP PLEASE!!!!!
if count ibis is correct the answer would be 15400 accroding to another person you would get 15, 022.9 which is correct?

Chemistry
C2H6 --> 2CH3 at a temperature where the half-life is 21 minutes. If the initial concentration is 8.0 mM, what would the concentration be after 46.0 minutes? How long would it take to convert 95% of C2H6 at this temperature?

calculus
Maximimum profit: you operate a tour service that offers the following rates: (1) $200 per person if 50 people (the minimum number to book the tour) go on the tour. (2) for each additional person, up to the maximum of 80 people total, everyones charge is reduced by $2. it cost...

algebra 1
solve by substitution. 0.5x+0.25y=36 y+18=16x

Chemistry
how many moles of lead (II) sulfate will be produced when 500 grams of magnesium sulfate is allowedto react with lead (II) nitrate?

government
why was amendment 17 significant and how were the state governments represented before this amendment?

speech
This might be a hard question to answer but I need an example for my speech for speech class. My speech is a persuasive on why you should foster an animal. I am talking about the benfits and how learning responsibility is a benefit. I know there are organizations out there tha...

Another Question
the friday after thanksgiving so this year its the 25th

Another Question
are you talking about 8th grade in school? No school just gives out awards. You can sometimes get awards if you participate in sports such as track, softball, etc.

Another Question
Each grade gets tougher as you go allow. For me 8th grade was not that bad. The grades that you get in 8th grade do not go towards your high school gpa unless you are taking a high school credit course. But, even so, you still want to try your best! If you are in 8th grade or...

Question
I website I like is student questions . com

Chemistry
In an organic chemistry lab, why is the organic layer usually the upper layer in the separatory funnel while the aqueous layer is usually the bottom layer?

Chem
So, for the rate of formation of C, would it be 2.5E-5 x (5/4)?

Chem
Consider the following reaction: 6A + 2B 5C + 4D Determine the following rates at a time when the rate of consumption of B is 2.5E-05 M/s. a) rate of consumption of A M/s b) rate of formation of C M/s c) rate of formation of D M/s d) rate of reaction M/s

algebra 1
write an equation for the line that is perpendicular to the given line and that passes through the given point. (6,4);y=3x-2

algebra
Suppose that Jane borrows 7800 dollars from a bank on April 24 at an annual rate of 7 percent simple interest. How much does she owe on August 14 of the same year?

reading
whay would a leaf be a good rug for a lady bug

Chemistry
In the experiment shown below, you add some salt to water. A = All of the solid dissolves (no solid at the bottom). B = You add more water and the solid stays dissolved. Select all of the following that are true about solutions A and B. The same number of ions are dissolved in...

Trig
Im having serious issues with verifying Trig. identities. Please help! Here is an example: (tanX-secX)^2= 1-sinX/1+sinX

calculus
water in a paper conical filter drips into a cup. let x denote the height of the water in the cup. if 10 in^3 of water are poured into the filter, find the relationship between dy/dt and dx/dt so the paper filter is 4 inches tall whith a radius of 2 inches. x is the height of ...

calculus
a billboard 20ft tall is located on top of a building with its lower edge 60 ft above the level of a viewers eye. how far from a point directly below the sign should a viewer stand to maximize the angle (theta) between the lines of sight of the top and bottom of the billboard....

Chem
The coordination compound has five stereoisomers (geometric plus optical isomers). Select all that apply... A:NH4[Pt(NH3)Cl3] B: tris(ethylenediamine)cobalt(III) sulfate C: tetraaquadichloronickel(IV) chloride D: [Co(NH3)2(en)Cl2]Cl E: [Co(en)2Cl2]Br F: sodium hexacyanoferrate...

physics
a laser beam with wavelength 632.8nm is incident normal to the plane of a diffraction grating with a slit separation d=2000nm. if the diffraction pattern is viewed on a screen 1m from the grating, find the distance separating the first, second, adn third maxima in the pattern.

speech
I am doing a speech on how to decorate a cupcake. But.. i do not know how to start it. I need an attention grabber any ideas?

physics
When the Sun is directly overhead, a hawk dives toward the ground at a speed of 3.07 m/s. If the direction of his motion is at an angle of 57.2 ◦ below the horizontal, calculate the speed of his shadow along the ground. Answer in units of m/s

calculus
im having so much trouble figuring out how to get these answers. i already know the answers i just need to figure out how to get them... directions: find the points of inflection and discuss the concavity of the graph of the function... 1. f(x)=(1/2)x^4+2x^3 2. f(x)=x^3-6x^2+1...

Chemistry
Sorry, I need to clarify. My question is why does a precipitate begin to form even though the solution is still basic (before enough HCl is added to make it acidic). Enough HCl is added to make the solution acidic, then it is submerged in an ice bath where the precipitate cont...

Chemistry
You isolate an acidic compound in an experiment by first separating it from the organic layer. Then you have a solution containing a salt of an acid. You acidify it using concentrated HCl. A precipitation begins to form while the solution is still basic.. why? You continue the...

Biology
35.49

Chemistry
Would this be the quickest/most efficient method: Take a small test tube, add roughly 1mL of water. Add a single drop of one of the unknown solutions. If the drop is miscible with water then it is from the aqueous phase; if it sinks to the bottom (or floats) it is the organic ...

Chemistry
During an experiment involving separation, you forget to label your beakers and you are unsure of which beaker contains the aqueous layer and which contains the organic layer. How could you quickly and efficiently determine which one is the aqueous layer?

Algebra 1
oh wait never mind. I see my mistake now. Thanks for the help.

Algebra 1
5. And wouldn't it be -12n?

Algebra 1
3n+40=-6(-2n+1)+1

Algebra 1
Thank you so much.

Fibonacci Numbers
I need to find f24. I know F23=28657 and f25=75025. I have figured out that F24 is 46368 using F(n)=F(n-1)+F(n-2). My problme is asking me for two values of n for which Fn=n. I do not understand what it is asking.

calculus
water is poured into a conical paper cup so that the height increases at the constant rate of 1 inch per second. if the cup is 6 inches tall and its top has a radius of 2 inches, how fast is the volume of water in the cup increasing when the height is 3 inches?

calculus
the cross section of a 5-ft long trough is an isosceles trapezoid with a 2 foot lower base, a 3-foot upper base, and an altitude of 2 feet. water is running into the trough at a rate of 1 cubic foot per minute. how fast is the water level rising when the water is 1 foot deep?

math
A ladder is resting against a wall. the foot of the ladder is 8 feet from the wall, and the top of the ladder is 19 feet from the ground. FIND THE slope of the ladder

Fibonacci Numbers
I posted the question several days ago and Mathmate helped to guide me along. I am just unsure if I do not understand what he is saying or if I did complete the problem right. I would appreciate any input. 1.618034 - -.618034 = 2.236068/sqrt 5 = 1.00000 I understand how to use...

calculus
a large ferris wheel is 100 feet in diameter and rises 10 feet off the ground. each revolution of the wheel takes 30 seconds. A) express the vertical distance "H" of the seat off the ground as a function of time "t" if t=0 corresponds to a time when the sea...

psychology
How do the ideas of positive psychology differ from the traditional model of illness?

Biology
What is the first step in replication?

Fibonacci Numbers: Understand one part not another
I understand how to use a calculator to write the decimal point using the golden ratio which is 1.618034 and the conjugate is -.618034. I also know that the relationship between the decimal expansions is that everything to the right of the decimal is the same except one is neg...

Check Fib. Number problem please
For any prime number p except 2 and 5, either Fp-1 or fp+1 is divisible by p. If I showed that this is true for p=7, the answer should be F8---is this correct because f8 is 21. P=11 would be divisible by 55 which is F10.

physics
is the speed of the cannon ball relative to the car or the ground??

Chemistry
A .1360 g sample of a mixture of magnesium and calcium carbonates when treated with HCL evolves 32.25 cm cubed of carbon dioxed measured dry at STP. Calculate the percent of magnesium carbonate in the mixutre.

chemistry
What is the pH of a solution prpared by mixing 50.0 ml of .200 M HCLO4 with 10.0 ml of .100 M KOH

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