# Posts by Serena

Total # Posts: 262

**Physical Science 9th grade**

Never mind then

**Physical Science 9th grade**

Anyone?

**Physical Science 9th grade**

Could someone please explain how I do this or provide a link explaining how. I am very confused. 1) a) Name 2 properties of waves that change if the wave changes media. b) Name a property that does NOT change when it changes media. 2) If the wavelength of a wave increases when...

**Math**

Rewrite the expression in terms of the first power of the cosine sin^8(x) how do i do this plz help !!

**Math**

The radius of the larger circle is 9cm. The diameter of the smaller circle is 11cm. Find the area of the shaded region. I don't understand this questions at all please help.

**Math algebra**

To find the average of a set of test scores we divide the sum of the test scores by the number of test scores. On her first four algebra tests,Paula wests scored 88,92,97,and 96. Write an equation that can be used to determine the grade paula needs to obtain on her fifth test ...

**Math comparing**

One box holds 16 crayons.Another box holes 24 crayons.Write a sentence using words that compares the crayons in two boxes.

**Trigonometry**

An airplane is 48 miles due north of a town. An airport is 29 miles North-West of the town. It is determined that the airplane is 34 miles from the airport. On what bearing should the pilot fly to get to the airport? Please show work if possibly, I'm having a hard time ...

**Math**

Fractions between 2/11 and 1/2

**Math**

God job but I think it is 2.5 cuz you divide 75 by 30 and you get 2.5 how did you get that answer?

**Social Studies**

Can someone check my responses please? I want to make sure I'm correct before submitting. The * is my response 1. How does the Pledge of Allegiance to the flag of the United States reflect the concept of natural rights? A. The Pledge of Allegiance includes the phrase "...

**Social Studies**

"We hold these truths to be self evident, that all Men are created equal, that they are endowed by their Creator with certain unaliable rights,..." -The Unanimous Declaration of the Thirteen United States of America Which of the following best paraphrases this ...

**Differential Calculus**

A clock has hands 1 and 1 3/5 inches long respectively. At what rate are the ends of the hands approaching each other when the time is 2 o'clock?

**drivers education**

#12 is D

**Differential Calculus**

Oh yes. Sorry sir. i just got confused. Thank you :)

**Differential Calculus**

But where did the a=5h come from?

**Differential Calculus**

The base of an isosceles triangle is 10 feet long and the base angles are decreasing at a rate of 2° per second. Find the rate of change of the area when the base angles are 45°.

**Healthcare Statistics**

No choices given. I am at a complete loss at where to begin with this problem.

**Healthcare Statistics**

using the following information, determine if the differences between the means are significant medical terminolgy class. Group A = number of word elements remembered by students using flash cards, group B= number of word elements remembered by students not using flash cards. ...

**Healthcare Statistics**

Given the following p values, which would be considered more significant? p ¡Ü 0.3 p ¡Ü 0.02 p ¡Ü 0.25

**Technology**

1. Who is an upstander? A. the person doing the bullying B. the person being bullied C. the person watching the bullying D. the person who tries to stop the bullying** 2. Which of the following is a place where cyberbullying DOESN’T occur? A. chat messages B. online ...

**la**

I agree

**Math**

Thanks

**Math**

1. Which of the following is a possible measure of the area of a square rug? A. 18 square feet B. 24 square feet C. 36 square feet** D. 48 square feet 2. Based on your answer to the precious question, what would the length of one side of the rug be? A. 4 feet B. 6 feet** C. 8 ...

**Comm Tech**

3/3 :)

**Science**

It is excretory because the Exretory system removes toxins and wastes. All this information can be found by look up "what is the excretory system do" or just "Exretory system". I think you might go to Texas connection academy because I recently took this ...

**diameter/kg**

I got 0.2669 but wrong also

**diameter/kg**

What is the mass of water required to fill a circular hot tub 3.4 m in diameter and 1.4 m deep? Answer in units of kg.

**history**

3. All of the following aided in the decline of the Incan Empire EXCEPT (1 point) A. being conquered by the Mayans. B. Francisco Pizzaro's trap that helped capture and kill the Incan emperor and his men. ---- C. that the Spanish had superior weapons. D. that the Spanish ...

**history**

3. All of the following aided in the decline of the Incan Empire EXCEPT (1 point) A. being conquered by the Mayans. B. Francisco Pizzaro's trap that helped capture and kill the Incan emperor and his men. C. that the Spanish had superior weapons. D. that the Spanish brought...

**history**

1. The Inca's huge empire was located in which mountain chain? (1 point) A. Rocky Mountains B. Alps C. Andes----- D. Amazons 2. The Incan people believed their emperor was related to whom? (1 point) A. Cuzco B. Quipo C. the god of Earth D. the sungod----- 3. All of ...

**Calculus**

What would the limit be for the following problems? lim (square root (x+3)) x--> 1 I thought it would be 1.4 lim (1/x) x--> 7 I thought it would be 0 or .1 but neither of those show to be correct. Thank you!

**Math**

nvm. i figured it out :)

**Math**

The difference between two numbers is 45. Three times the larger number less five times the smaller number equals 75. What are the two numbers?

**Stats**

Makers of a new pain-relieving medication claim that it relieves chronic pain faster than the current top-selling pain reliever on the market. A double-blind experiment was conducted in which 10 people who experience chronic pain were randomly selected to take either the new ...

**Chemistry**

Why does AgCl dissolve in NH3 but AgBr and AgI don't? KSP of AgCl = 1.8 x 10-10 KSP of AgBr = 5.0×10–13 KSP of AgI = 1.5 x 10-16

**Precalculus**

A rancher wishes to fence in a rectangular plot of land and divide it into two corrals with a fence parallel to two of the sides. If she has 300 yd of fencing available, how large an area can the plot have? This is what I have so far: A=xy 300=2x+3y

**CHECK ANSWERS PLEASE!!!**

Thanks Alexis, I got 4/4

**chemistry**

How many moles of hydrogen would be obtained if 2.7g of aluminium reacts with excess hydrochloric acid?

**Trigonometry**

Find exact value of each expression sec^-1 (2root3) / 5 I have no idea what to do to make that into a value. I know that sec^-1 is in quadrants one and two, but I'm not sure how to use that to solve the problem. Thank you!

**Science**

i think D

**physics**

An object having a net charge of 18.2 μC is placed in a uniform electric field of 790 N/C directed vertically upward, i.e. in the direction opposite gravity. What is the mass, in grams, of this object if it "floats" in the field? (Assume g = 9.80 m/s2.)

**physcis**

Two small beads having charges q1 and q2 are fixed so that the centers of the two beads are separated by a distance d shown in the figure. A third small bead of charge q=10.0 x 10-9 C is placed between both charges a distance x from q1. a) If q1 = 31.0 x 10-9 C, q2 = 26.0 x 10...

**math- weighted averages**

.3n + .5(500+ n)=300 n = 62.5ml .3n +.5(500 + n) =300 .3n + 250 + .5n = 300 .8n + 250 =300 .8n = 50

**physics**

A harmonic wave is traveling along a string. If the oscillator that generates the wave completes 23 vibrations in 18.50 seconds and if it takes a crest 20.21 seconds to travel 168 cm along the rope. What is the wavelength of the wave? Answer in cm.

**Physics**

In a horizontal spring-mass configuration, the position of the 0.52 kg mass is described by [x = (1.09 m) sin(2.70t)] a) What is in meters the amplitude of these oscillations? b) What is in m/s the maximum speed of the mass under these conditions? c) What is in Joules the ...

**physics**

The position of a 0.31 kg object attached to a spring is described by [x = (0.85 m) sin(2.37πt + 0.35)] a) What is the amplitude of oscillations in m? b) What is in meters/second the maximum speed of the oscillating object? Answer in meters/seconds . c) Find in meters/...

**physics**

The position of a 0.43 kg object attached to a spring is described by [x = (0.49 m) cos(1.25πt)] a) What is the amplitude of oscillations in m? b) What is in meters/second the maximum speed of the oscillating object? Answer in meters/seconds . c) Find in meters/second the...

**physics**

Two masses are connected by a light string passing over a frictionless pulley as shown on Figure. The M2= 6.1 kg mass is released from rest at height h = 2.8 m . We are given that M1=2.7 kg and I, the moment of inertia of the pulley is I = 0.198 kg m2 and its radius is R = 0....

**Physics**

A solid sphere of mass 2.07kg rolls up an incline with an inclination angle of 24.40°. At the bottom of the incline, the center of mass of the sphere has a translational speed of 2.80m/s. a) What is in J, the linear kinetic energy of the sphere at the bottom of the incline...

**Physics**

Consider the rods plus disc system shown in the Figure. The rod has a length L =0.50 m, and mass M = 0.270kg. The large disc has a radius of R = 0.130m and mass m=0.810kg. The second disk should be treated as a point mass of 0.405kg. It is glued to the rod at position X = 0....

**physics**

An m=150 g block hits an M= 265 g block initially at rest on a horizontal surface. After impact they stick together and slide 7.47 m before coming to rest. The coefficient of friction between blocks and surface is 0.39. a) What is in m/s the speed of both blocks immediately ...

**physica**

Consider the rods plus disc system shown in the Figure. The rods are identical. They have a length L =0.50 m, and mass M = 0.250kg. The disc has a radius of R = 0.130m and mass m=0.750kg. Both rods are glued to the disk as shown with X = 0.25m. The system behaves as a compound...

**Physics**

A block of mass 11.2 kg slides from rest down a frictionless 24.0° incline and is stopped by a strong spring with a spring constant 31.3 kN/m (note the unit). The block slides 8.90 m from the point of release to the point where it comes to rest against the spring. When the...

**AP Chem**

Sorry if I was being unclear. Yes, this is an experiment that I conducted. We calculated the temperature change between one reactant and when the reaction occurred. The first reaction had a temp change of 12.5, the 2nd had 1.10, and the third had 5.8 degrees C. I've also ...

**AP Chem**

Reaction 1: NaOH + HCL --> H20 + NaCl delta H of -100.332 kj/mol Reaction 2: NaOH + NH4Cl --> NH3 + H20 : delta H of 358.639 kj/mol Reaction 3: HCl + NH3 --> NH4Cl : delta H of -51.701 kj/mol Use your answers from question 2 above and Hess's law to determine the ...

**Calculous Pre**

A population grows from 11,000 to 15,000 in three years. Enter your answers to three decimal places. Assuming the growth is exponential, find the growth rate and continuous growth rate Growth rate ______ %? Continuous rate _________ %?

**English (Grammar)**

Would it be grammatically correct to say "Lastly, the Puritan values of appeasing towards God in every thing they do..." or "Lastly, the Puritan values of appeasing God in every thing they do..." I'm thinking the second one is grammatically correct but ...

**Science**

A.) A runner is jogging at a steady 6.7 km/hr. When the runner is 3 km from the finish line, a bird begins flying from the runner to the finish line at 20.1 km/hr (3 times as fast as the runner). When the bird reaches the finish line, it turns around and flies back to the ...

**chemisty**

Hi, I'm a 10th grade student and this is how I would look at it... So what is being oxidized is what is losing electrons. So take Copper for example. Copper is going from a 1+ charge to no charge as a solid...so is it gaining an electron or losing. Now think of Iron. Iron ...

**Algebra**

Hi, I'm a 10th grade student and this is how I think the problem would be solved... So let x = the amount you need to sell .03x = $420 + .02x .01x = $420 x = $42,000 So you would need to sell at least $42,000 in the first job be equal to the second job. Hope this helps!

**Chemistry**

Never mind, I figured out I needed to convert the moles to grams and then I would use the q = mc delta t.

**Chemistry**

The heat capacity of aluminum is 24.4 J/mol times degrees C. How much energy is released when 5.00 g Al is cooled from 50 degrees C to 30 degrees C. a) 2440 J b) 90 J c) 3.7 J d) 488 J I said A, but the answer sheet says that the answer is B. Can someone please explain how ...

**Chemistry**

I know what I did wrong. Some reason I divided the moles of C10H8 by .0120 instead of .120, so my answer was 11 times the answer it should have been. Thank you very much!

**Chemistry**

I'm really confused on this question so if someone could show the steps and how to get the answer, that would be great. I understand that you would use delta T=Kbm, but don't know how to use the equation to find the answer. Thanks!! Calculate the boiling point of a ...

**Algebra 1**

While playing a game, Rachel pulls two tiles out of a bag without looking and without replacing the first tile. The bag has two colors of tiles--black and white. There are 10 more white tiles than black tiles. a. Write and simplify an expression that represents the probability...

**Algebra 1**

the answer for a is x(x+10)/ (2x+10) (2x+9) the answer for b is 0.20

**Social Studies**

All these plp are wrong! Listen i check them all, if you listen to these answers you will get a 3/9!!!! Don't do it! Pick up your book and learn. Just use the book bc you will fail using this. Jiskha should be sued for all this bad behavior and Mrs.sue is not always Mrs....

**Chemistry**

Ok, I think I get it. Thank you both very much!

**Chemistry**

I'm still a little bit unsure. The website didn't really specify why the ions disassociate with each other and associate with hydrogen bonding

**Chemistry**

So I am trying to understand in molecular terms the solubility of NaCl in water. So there are intramolecular forces that are mostly ionic between the ions, creating this partial positive, partial negative substance. And the intermolecular forces are also ionic. Ionic forces ...

**English**

Dr. Seuss is an authorwhovis famous for his original and clever children's book

**History**

Both Hitler and Churchill were gifted orators. Compare their styles. I was thinking something like that they both used nationalism to make themselves popular within the people. And they spoke to create nationalism in their country. Does this make sense and also how do their ...

**Math 10**

Algebraically, determine the vertex form of a quadratic relation, if the vertex is at (-1, 2) and the point (1, -10) is on the parabola. Show all of your steps. I know that the formula is y=a(x-h)suared+ k but how do i apply these numbers to this formula? Thank you!

**Math 10**

Thanks alot guys! Both of your answers were very helpful.

**Math 10**

Hello, Is there easiest and simplest way to do this question? "A baseball is thrown from the top of a building and falls to the ground below. The height of the baseball above the ground is approximated by the relation h = -5t2 + 10t + 15, where h is the height above the ...

**English**

Never mind, I have received an answer to this, thank you

**English**

I have an essay and this is one part of my thesis... "In the nineteenth century, some ways the middle class participated in revolutions was by establishing liberalism, one way was through literature, and through the revolutions of 1848." I wasn't sure if the &...

**Lit**

Ok, I'll edit it. Thank you!

**Lit**

I have an essay and this is one part of my thesis... "In the nineteenth century, some ways the middle class participated in revolutions was by establishing liberalism, one way was through literature, and through the revolutions of 1848." I wasn't sure if the &...

**Chemistry**

Ok, makes sense. Thanks!

**Chemistry**

In a heating and cooling curve, I understand that the flat part means that the bonds are either forming or breaking, depending on if the input of energy is increasing or decreasing, but what is happening to the bonds in the slanted parts? Thanks!

**Chemistry**

I have discovered a new chemical compound with the formula A2B. If a saturated solution of A2B has a concentration of 4.35x10-4M. a) What is the concentration of B2- ions? b. What is the concentration of A1+ ions? c. What is the solubility product constant for A2B? Can you ...

**Chemistry**

What number is the rate ?

**Chemistry**

Did anyone end up getting this. if you plug in the numbers above you still need the retain rate to find k. How do you do that??!!

**Chemistry**

An atmospheric scientist interested in how NO is converted into NO2 in urban atmospheres carries out two experiments to measure the rate of this reaction. The data are tabulated below. A: [NO]0 = 9.63 × 10-3 M, [O2]0 = 4.1 × 10-4 M t(s) 0/3.0/6.0/9.0/12.0 [O2] 4.1/...

**Chemistry**

Are cold alkalis the same as bases? If not, then what is the difference? Can you also give some examples if they are not the same? Thanks!

**Title**

Okay, thank you!

**Title**

Hi I need help thinking of a title for my graphic novel. It is about India and its exploitation of children. Could someone help me think of a cool title and an idea to make the title look unusual. Like maybe a bleed or something. Thanks!!

**Algebra II**

1. 4^x - 3(4^-x) = 8 I got where 4^x = 4 + square root (19), but I can't solve further. The answer is (log (4 + root (19)) ) / (log 4). 2. log (x^2) = (log x)^2 Solve for x Thanks!

**Math**

A rectangular box has a length of 12 inches and a width 4 inches. The length of the three-dimensional diagonal of the box is 14 inches. What is the height of the box?

**Math**

A rectangular box has a length of 12 inches and a width 4 inches. The length of the three-dimensional diagonal of the box is 14 inches. What is the height of the box?

**Math**

A 12-foot ladder is set up 5 feet from the base of a building. How far up the building does the ladder reach? Round your answer to the nearest tenth of a foot.

**calc**

If z = 2cis 60°, find z^4 in rectangular form.

**Math**

thanks people

**math**

Yes, you are right. Use distribution and multiply each number in the parenthesis aka the "10x" and "-12" by -3. So it would be 10x(times -3) - 12(times -3) -30x - -36 -30x + 36 Thats your answer. Hope this helps! Serena, a 10th grade student

**Math**

1. So you know that the slope intercept form is y=mx+b, right. And m is the slope. So in this case there is no straight out coefficient, but x is also equal to 1x. Therefore one is your slope. 2. So first bring -6 to the opposite side of the equation by adding 6 to each side. ...

**Chemistry**

Do pipettes blow up like balloons when they are heated. Why or why not?

**Chemistry**

Oh sorry. The actual question is... Explain what happens at the molecular level for something to dissolve.

**Chemistry**

How could 2 molecular compounds react to create a precipitate and an aqueous solution?