# Posts by sarah

Total # Posts: 5,805

civic education
Nigeria,Ondo State

Science
The half-life of randon-222 is 8 days. What was the original mass if 6 grams remains after 24 days?

Chemistry
A 10.0 L container contains 1.0 L of solution of a gas. Assume [gas]=1.5x10^-4 M in solution when 2 mol of gas remain in gas form. If 1 mol of gas is removed from the gas phase, what will be the new concentration of the gas in solution? What is the value of k?

Math
the amount (in milligrams) of a drug in the body t hours after taking a pill is given by A(t)=30(0.8)t . (a) What is the initial dose given? (b) What percent of the drug leaves the body each hour? Percent: (c) What is the amount of drug left after 9 hours? (d) What is the ...

Health
Answers: 1. B 2. C & D 3. C

Physics
The displacement of a block of mass 439g 439 g attached to a spring whose spring constant is 66N/m 66 N m is given by x=Asin(ωt) x A s i n ω t where A=12cm A 12 c m . In the first complete cycle find the values of x x and t t at which the kinetic energy is equal to ...

The speed limit near a school is 30km/h but Joe Cool thinks he can ignore it. He is driving at 60km/h. To make matters worse, he is talking on his cell phone. Suddenly a child rides his bicycle out of school grounds and across the road on the pedestrian crossing. The maximum ...

Personal learning plan (english?)
What are some visual, auditory, reading/writing and kinaesthetic learning activities done in high schools?

science
Imagine a Rip van Winkle type who lives in the mountains. Just before going to sleep, he yells, "WAKE UP", and the sound echoes off the nearest mountain and returns 7.6 hours later. Find the distance between Rip and the imaginary mountain. I have this equation s= v(...

physics
A bullet of mass 0.08kg is fired horizontally into a 10kg block which is free to move. If both bullet and block move with a velocity of 0.6m/s after the impact, find the velocity with which the bullet hits the body

English
Please, I don't want to complicate my life, so, what's the best effective way to write a topic sentence for my body paragraphs?

Calculus
Using the definition of the derivative, find the equation of the tangent line to y=2x-1/2 at (1/2,-1) Thanks!!

A guy riding a buffalo is chasing you at a top speed of 50 km/h, you are well ahead of the rider by 2 km, but your speed is only 20 km/h. How much time do you have to come up with a better plan?

Physics
A guy riding a buffalo is chasing you at a top speed of 50 km/h, you are well ahead of the rider by 2 km, but your speed is only 20 km/h. How much time do you have to come up with a better plan?

Introductory Accounting
The question is Burlin company starts the year with \$188,000 in assets and \$37,600 in liabilities. Net income for the year is \$47,000, and no dividends are paid. How much is owners' equity at the end of the year? So what I thought what i would have to do is add the 188,000...

Social Studies
That is not a valid link

Social Studies
Hi, I'm having a really hard time understanding this concept. I know the answers because my teacher told us them but I don't know why they are the answers. Could you explain them please? 1. Professor Roth's rule is that any student who uses a cell phone in class ...

science
If exponential growth occurs in the population of a species of predator, the population of its prey will most likely decrease quickly. increase slowly. stay the same. experience exponential growth.

Physics
A 300g particle oscillating in SHM travels 11cm between the two extreme points in its motion with an average speed of 65 cm/s. a) Find the angular frequency b)The maximum force on the particle c)The maximum speed

Science
Describe one observation astronomers use to show that the universe is expanding

Science
-Explain how and when the universe formed according to the big bang theory? -Explain how and when our solar system formed? -Describe one observation astronomers use to show that the universe is Expanding?

maths/physics
4. Write down a diﬀerential equation to express each of the following relationships: (a) The rate at which the volume of a sphere changes with radius is proportional to the square of the radius. (b) Gravitational attraction F between two given bodies of masses m1 and m2...

Physics (
3. Terminal velocity of an object in freefall is given by Vt = root 2gMA/Cdñ , where g is gravitational acceleration,Cd is the coefficient of drag, p is air density, and MA is the ratio M/A of mass M to ‘downwards facing’ area A. For a falling sphere of radius...

Physics (Gravitation)
sorry, to correct the question. Ve= root 2GM/r Where G is the gravitational constant 6.8x10^-11, M is 10^22 + r^4 if possible, please can you provide a step by step answer to the question

Physics (Gravitation)
2. To leave the gravitational ﬁeld of a planet, a space rocket must be launched at an escape velocity of: ve =r2GM r , where G is the gravitational constant G ¡Ö 6.8¡Á10−11Nm2/kg2, M is the mass of the planet and r is its radius. Suppose ...

ELA
Explain 1 External and 1 Internal conflict From the book Found by: Margret Peterson Haddix. Make sure it includes: who it involves and how it is solved.

math
I am an even. number the sum of my digits equals 7. I am greater than 40 and less than 50. what number am I?

Science
1. Which of the following traits is acquired? A.) The number of petals that grow in a plants flower B.) the wing shape of a wild bird C.) The ability of some gorillas to learn sign language** D.) A cheetah’s ability to run faster than any other land animal 2. The height ...

ELA.. English Language Arts

Explain 1 External and 1 Internal conflict From the book Found by: Margret Peterson Haddix. Make sure it includes: who it involves and how it is solved.

Help...
What are the major stars of Gemini?? Name 4 of them... Explain the myth behind the constellation "the twin"

Help....
-list some of George Washington precedent -describe Thomas Jefferson achievement before becoming president of the United States - why was Lewis and clark expedition important?

Science
Thank you so much I got them all right!

Physics
15o

math
Find the domain of the given function f. (Enter your answer using interval notation.) f(x) = 1/(x2 − 8x + 16)

math
A right triangle is drawn on a coordinate plane. Its base is the line segment between (2, 2) and (9, 2). The hypotenuse is a line segment that begins at (2, 2) and has slope 1.25. Find the coordinates of the third point.

Precalculus
Find every point on the horizontal line y = 5 that is a distance of 5 units away from the point (6, 1).

French
are these sentences correct J'ai mangé des pâtes delicieuses J'ai mangé de delicieuses pâtes

Help....
Should cellphone be used at school everyday!!! Why or why not...

Physics (Feilds)
Show that the gravitational potential at the surface of the Earth is -64 MJ kg-1, given the surface gravitational feild strength is 9.8 N kg-1 and the mean radius of the Earth is 6400 km.

chemistry
describe what happen when a piece of wet red litmus paper is passed through a hydrogen gas.

chemistry
describe what happen when a piece of wet red litmus paper is passed through a hydrogen gas.

Chemistry
At pH 9 what will the ratio of ammonium to ammonia be? The pKa of ammonium is 9.24?

Physics
Hi Damon Can you please explain how you got 19 ? and why is it being divided by 1.7 ? Thanks! Sarah

Physics
The diameter of our disk-shaped galaxy, the Milky Way, is about 1.7E+5 light-years (ly). The distance to the Andromeda galaxy, which is the spiral galaxy nearest to the Milky Way, is about 1.9E+6 ly. If a scale model represents the Milky Way and Andromeda galaxies as dinner ...

Algebra/math
A teacher is showing her class how to fold a square piece of paper to create a paper cup. One of the steps is shown below. According to the measurements, what is the length of x, in inches?

Math
A cookie recipe calls for 2/3 of a cup of flour and makes half a dozen cookies. How many cookies can you make if you have 9 cups of flour and want to use it all? I came up with an answer of 81 cookies by using a proportion. 2/3 over 6 (because half a dozen cookies is 6 cookies...

Math
The record for the fastest speed on a bicycle is 133 kilometers per hour. How long would it take a person traveling at this speed to travel 365.75 kilometers

Chemistry
The concentration of barium ions in any solution can also be determined via gravimetric analysis. An impure sample of barium nitrate with a mass of 1.234 g, is completely dissolved in water and the resulting solution is reacted with an excess of aqueous sodium sulfate. A ...

Chemistry
The concentration of barium ions in any solution can also be determined via gravimetric analysis. An impure sample of barium nitrate with a mass of 1.234 g, is completely dissolved in water and the resulting solution is reacted with an excess of aqueous sodium sulfate. A ...

physics
Assume the truck is going at v0 = 25 m/s, and you're 20 m behind the truck. You decide to accelerate at a = 1.0 m/s2 to pass the truck. To pass safely, you also want to pass the truck by 20 m before moving back to the lane. Part A ) Estimate the time interval needed to ...

Physics
Thank you so much!!!

Physics
what would I solve for when I do the conservation of momentum at the bottom of the block with the bullet?

Physics
A 0.15kg bullet is fired into a 1.85kg block that is hanging from a 45cm string. What minimum initial bullet speed is required if the bullet and block are to make one complete revolution? Please show all work. I need this question answered as soon as possible!

physics
A ball is thrown up onto a roof, landing 4 sec later at height of 20m above the release level. The balls path just before landing is angled at 60 degree with the roof. a) find the horizontal distance d it travels. b) what is the magnitude of the balls initial velocity? c) what...

Math
describe a situation where a trend line would be useful

48/3 = 16 2/3= 16x2= 32 she sold 32 muffins

Math
log2(-3sinx)=2log2(cosx)+1 solve for x

Chemistry
Compound X contains only carbon, hydrogen, nitrogen, and chlorine. When 1.00 g of X is dissolved in water and allowed to react with excess silver nitrate, AgNO3, all the chlorine in X reacts and 1.95 g of solid AgCl is formed. When 1.00 g of X undergoes complete combustion, 0....

math
Roma spent 30% of the money she bought to the mall..If she spent 450.00 only,how much did she have with her when she went to the mall?

math
after spending 80% of her money Lei has P100.00 left. How much was her money before

science
Suppose the height of the net is 0.800 m , and the court's border is 11.2 m from the bottom of the net. Use g =10 m/s2 and find the maximum speed of the horizontally moving ball clearing the net..

Math
A contractor buys 14 yd of nylon carpet and 20 yd of wool carpet for \$1738. A second purchase, at the same prices, includes 16 yd of nylon carpet and 25 yd of wool carpet for \$2102. Find the cost per yard of the wool carpet.

pobability
Suppose that 16% of the CD's that are distributed are defective. If you choose 5 CD's randomly, what is the probability that at least 1 of them is defective?

Math
How do integrate this with respect to x? integral of ((x^y)/y!)e^(-2x) from 0 to infinity The e is an exponential. The answer is supposed to be (1/2)^(y+1) but I don't know the steps to getting it.

math
Measuring number of surface of the rectangle is 128.If we reduce the length of 4 times, then the number is 96cm2.What is the perimeter?

geometry
c//d,<7 and< are= corresponding angles

Chemistry
Nevermind - I think I see what I did wrong. I was using 25 mL as my volume for hydrogen peroxide, when I should have been using 20 mL since that was the volume being added. Though I don't necessarily understand how that's the volume that needs to be used.

Chemistry
a 5.000ml aqueous sample containing hydrogen peroxide as diluted to 25ml and analyzed by titration with permanganate. 2MnO4- + 5H2O + 6H+ --> 5O2 + 2Mn^2+ + 8H2O The sample required 42.8 mL of 0.0175 M permangante to reach the end point. What is the concentration of H2O2 in...

geography
describe the impact the french and Indian war had on Florida?

Chemistry
Is it true that the higher the boing point, the higher the vapor pressure?

Chemistry (I tried to do more)
I think the order of decreasing vapor pressure is Acetamide, Acetic Acid, Propanal, and Isobutane. The trend is the higher the boiling point, the lower the vapor pressure. Is this right? If not, please explain.

Chemistry
Rank the following in order of decreasing vapor pressure, and briefly explain the observed trend in vapor pressure: Acetic Acid Isobutane Acetamide Propanal

Chemistry
Would copper (II) phosphate be nonpolar?

Math
The distance a bicycle travels with each turn of its wheels is about 3 1/7 times the tire diameter. The tires on Mike's bicycle have a diameter of 24 1/2 inches. How far does it travel with each turn of the wheels?

Chemistry
How can you tell if a compound is polar or nonpolar? Is it just by lewis structures? what would copper (II) phosphate be?

Chemistry
How do you determine it then?

Chemistry
When given different elements and asked for the highest boiling point, do you figure out the molar mass and pick the highest one as the highest boiling point?

Math
6x=24

Math
That polynomial can't be factored. Double check that you copied the equation correctly, then check out mathportal dot org.

Social Studies
Describe the role of shariah in Islam. What types of laws would one expect to find within Islamic governments, and how are they enforced? This was one of my questions on my homework, and I can't figure out a solid answer to it. Thank you!

physics
A 0.014 kg bullet is fired straight up at a falling wooden block that has a mass of 4.0 kg. The bullet has a speed of 700 m/s when it strikes the block. The block originally was dropped from rest from the top of a building and had been falling for a time t when the collision ...

phyics
Cheryl is riding on the edge of a merry-go-round, 2m from the center, which is rotating with an increasing angular speed. Cheryl’s tangential acceleration is 3.0m/s2. At the instant that Cheryl’s linear speed is 4.0m/s, what is Cheryl’s total acceleration? ...

Chemistry
The intreval volume of a clorimeter was1.12L. A sample of gas of 1.863g of nonae was added, and the closed calorimeter then had added oxygen until the pressure was 10.0atm na dht etemp was 23.1 C.Write the full balanced equation of the combustion of the nonae in the ...

Chemistry
Automotive airbags inflate when sodium azide, NaN3, rapidly decomposes to its constituent elements according to the chemical equation, 2 NaN3 -> 2 Na + 3 N2. How many grams of nitrogen are produced when 1000 milligrams of sodium azide decomposes?

differential equations

differential equations
Convert x''+ sin(x) = 0 into a first order system of equations. (x'' refers to the second derivative of x). I tried: y1 = sin(x) y2 = x' {y1' = cosx {y2' = -sinx Not sure if I did it right.

Algebra

Algebra
1. determine whether the equation represents a direct variation , if it does find the constant of the vartion 2y=5x+1

Phyics
The foci of the elliptical path for an Earth satellite are __________. A) one at Earth's center and the other elsewhere B) one atop the other at Earth's center C) both inside Earth D) both outside Earth

geometry
given: -n+6=8n+6n prove:n=0

Chemistry
ok I set up the first one right, and got P=.998 atm The after composition makes sense and I got P = 20.0 atm Are these correct?

Chemistry
Calculate the pressure of 4.80g of ozone, O3, in a 2.45 L flask at 25 degrees C. Assume that the ozone completely decomposes to the molecular oxygen. 2O3(g) --> 3O2(g) Calculate the pressure inside the flask once the reaction is complete.

Chemistry (Check)
correct

Chemistry (Check)
What is the volume of the gas in a balloon at -195 degrees C if the balloon has been filled to a volume of 5.0L at 25 degrees C? Vf = 1.3L

Chemistry
Is it just .8252 kg/cm^3? because multiply 1000cm^3 / 1000kg

Chemistry
Calculate the density of methane gas, CH4, in kilograms per cubic meter at 25 degrees C and 956 mmHg. I got .8252 g/L but am getting confused with the converting units.

Chemistry
Calculate the pressure in an evacuated 250mL container at 0 degrees C when the O2 in 1.00 cm^3 of liquid oxygen evaporates. Liquid oxygen has a density of 1.118 g/cm^3.

Science
Nonmetals are often brittle

Biology
to produce a substance

Post a New Question