# Posts by Rachel

Total # Posts: 1,553

**Chemistry**

did you write anything because it doesnt show

**science**

drbob222 can you please answer the science questions on my post

**science**

do you know anyone who can help me?

**science**

dr bob 222 or ms.sue can you please answer these questions

**math**

which number has the greatest value? a 3.5 b square root of 15** c square root of 1/16 d 26/100 which number is an irrational number? a 3.5 b square root of 36 c square root of 48 d 37/100*** If a is a rational number and b is an irrational number, then the sum a + b is A)...

**science**

1. Tommy performed an experiment to test the solubility of sodium chloride in water. After he completed his experiment, he discovered that he had a few unused grams of NaCl leftover in a beaker. What should he do with the excess NaCl? A. Pour the excess back into the original ...

**AP Calc. AB**

If f and g are functions such that f(g(x))=g(f(x))=x for all x in their domains, and if f(a)=b and f'(a)=c, then g'(b) =? a) g'(a)=1/c b) g'(b)=1/c c) g'(b)=-1/c d) g'(b)=1/a e) g'(a)=-1/c

**Chemistry**

3NO2(g) + H2O(l) → 2HNO3(aq) + NO(g) standard enthalpy: -133.5 Find the change in internal energy for this reaction. Enter in kJ.

**Statistics**

Suppose a certain species bird has an average weight of grams. Based on previous studies, we can assume that the weights of these birds have a normal distribution with grams. For a small group of 13 birds, find the margin of error for a 70% confidence interval for the average ...

**US History**

This is a letter from George Washington to Patrick Henry: September 24, 1787 I don't understand what his purpose and point of view is. Please help me!!! Dear Sir: In the first moment after my return I take the liberty of sending you a copy of the Constitution which the ...

**AP CALC. AB**

1.The position of a particle moving on the line y = 2 is given by x(t)= 2t^3-13t^2+22t-5 where t is time in seconds. When is the particle at rest? a. t =0.268, 2.500, and 3.732 b. t = 0, 1.153, and 3.180 c. t = 1.153, 2.167 and 3.180 d. t = 2.167 e. t = 1.153 and 3.180 2.A ...

**physics**

A cyclist maintains a constant velocity of 4.1 m/s headed away from point A. At some initial time, the cyclist is 244 m from point A. What will be his displacement from his starting position after 60 s?

**Economics**

explain why positive and negative externalities are market failures

**US History**

The Revolutionary War could be considered an international war. Explain if this statement is true or false using examples.

**US History**

Were the colonists politically independent before the French and Indian War?

**US History**

the seven years of war led to taxation without representation because of the debt that king george had to pay for. therefore this angered the colonies and was a turning point to english and colonists relationships

**US History**

i am writing an essay so i need to write about multiple reasons

**US History**

taxation without represent ions that the only one that i know

**US History**

Why was seven years of war a turning point in British colonial society and their relationship with England? Please give me 4 different reasons.

**physics**

A diver achieves a horizontal velocity of 3.76 m/s from a diving platform located 6m above the water. How far from the edge will the diver be when she hits the water?

**AP CALC. AB**

Let f(x)=3/x. If the rate of change of f at x = c is three times its rate of change at x = 2, then c = ?

**AP Calc. AB**

At how many points on the curve y=4x^5-3x^4+15x^2+6 will the line tangent to the curve pass through the origin?

**Social Studies**

angel, which answer did you get wrong?

**AP Calc. AB**

1.If an arrow is shot upward on the moon with a velocity of 50 m/s its height (in meters) after t seconds is given by H = 50t - 0.66t2. With what velocity will the arrow hit the moon? a. -49.5 b. -47 c. -50.1 d. -50 e. -51 2.If an arrow is shot upward on the moon with a ...

**math statistics**

A group of teenager smoking rate dropped 8.5% in 2007 from 17.6% in 2001 and 23% in 1997. 1. Calculate the probability that at least one in a group of 10 teenagers smoked in 2007.2. Calculate the probability that at least one in a group of 10 teenagers smoked in 2001. 1. ...

**statistics**

Teenage smoking rate dropped to 8.5% in 2007 from 17.6% in 2001 and 23% in 1997. 1. Calculate the probability that at least one in a group of 10 teenagers smoked in 2007. 2. Calculate the probability that at least one in a group of 10 teenagers smoked in 2001. 3. Calculate the...

**AP Calc. AB**

is it 57 m/s??

**AP Calc. AB**

If an arrow is shot upward on the moon with a velocity of 57 m/s its height (in meters) after t seconds is given by H= 57t-0.06t^2. With what velocity will the arrow hit the moon?

**AP Calc. AB**

Thanks Steve ur a life saver!!

**AP Calc. AB**

1.Which function is NOT continuous everywhere? A.y=(4x)/(x+1)^2 B.y=|x| C.y=(x)/(x^2+1) D.y=√(x^2+1) E.y=x^(2/3) 2.State the domain f(x)= √((x+6)) sinx 3. Let h(x) {(sin2x)/x, if x ≠ 0 {a, if x=0 find the value of a so that hi s continuousat x=0 a. it is sot ...

**US History**

What factors made New England so different from the middle and southern colonies? Consider such things as economics, environment, social make up, philosophy, and religion?

**US History**

Thank You!!!

**US History**

Why is the landing at Plymouth Rock seen as just as important as Jamestown, or more so, in the founding of our country?

**English**

Would just in this sentence be considered and adverb? Now when they were first made, the bears were covered with hair and had sharp claws. Would this be an example of adverb modifying a verb

**algebra**

Find the center and radius of the circle whose equation is 5x^2−6x+5y^2+8y−9=0.

**algebra**

Find the domain and range of: F(x)=sqrt(x)+16

**English**

What is the tone in When Grizzlies Walked Upright?

**Biology**

Is respiratory control more sensitive to small changes in arterial PO2 or in arterial PCO2?

**Biology - very urgent**

Is respiratory control more sensitive to small changes in arterial PO2 or in arterial PCO2?

**Marketing**

How would you classify Wal-Mart in terms of its position on the wheel of retailing versus that of an off-price retailer?

**Math**

At Lucy's Restaurant,1 3/4 a serving of tomato soup is cups. Lucy makes 63 cups of tomato soup each day. How many servings of tomato soup does she make?

**Chemistry**

Calculate the concentrations of all species in a 1.17 M Na2SO3 (sodium sulfite) solution. The ionization constants for sulfurous acid are Ka1 = 1.4× 10–2 and Ka2 = 6.3× 10–8. I found Na+ = 2.34 SO3^2- = 1.17 H2SO3 = 7.14 x10^-13 I can't find HSO3...

**Chemistry**

Phosphoric acid, H3PO4(aq), is a triprotic acid, meaning that one molecule of the acid has three acidic protons. Estimate the pH, and the concentrations of all species in a 0.200 M phosphoric acid solution. pKa1 = 2.16 pKa2 = 7.21 pKa3 = 12.32 Ok I haven't been able to ...

**analytic geometry**

the three vertices of a triangle are at A (-4,5), B(-5,3) and C (3,-4), show that the line joining the midpoint of the sides AC and BC is parallel and equal to one-half of AB . solve

**analytic geometry**

the three vertices of a triangle are at A (-4,5), B(-5,3) and C (3,-4), show that the line joining the midpoint of the sides AC and BC is parallel and equal to one-half of AB . solve

**science**

A comet is in an elliptical orbit around the Sun. Its closest approach to the Sun is a distance of 4.8 x10^10 m (inside the orbit of Mercury), at which point its speed is 9.1 x10^4 m/s. Its farthest distance from the Sun is far beyond the orbit of Pluto. What is its speed when...

**math**

what is the integral from 2 to 1 of 15sqrt(4x^2-3) dx

**science**

A 25 kg box is being pushed across the floor by a constant force ‹ 100, 0, 0 › N. The coefficient of kinetic friction for the table and box is 0.15. At t = 6.0 s the box is at location ‹ 14, 3, −4 › m, traveling with velocity ‹ 6, 0, 0 › m/s...

**Chemistry**

Fish breathe the dissolved air in water through their gills. Assuming the partial pressures of oxygen and nitrogen in the air are to be .20 atm and .80 atm respectively, calculate the mole fractions of oxygen and nitrogen in the air dissolved in water at 298 k. The ...

**geometry**

Ralph the monkey is looking down at a 31° angle from the top of a tree. There are bananas on the ground 12.4 ft from the base of the tree. If Ralph flies down from the tree at a diagonal path, shown in the diagram by x, what distance would he travel? Round to the nearest ...

**maths**

calculate the values of p and q Analytical geometry

**physics**

A moving object has a kinetic energy of 147 J and a momentum of 22.3 kg·m/s. a) Find the speed of the object. Answer in units of m/s

**Chemistry**

A small pebble is heated and placed in a foam cup calorimeter containing water at 25 °C. The water reaches a maximum temperature of 27 °C. If the pebble released 532.1 J of heat to the water, what mass (in g) of water was in the calorimeter? can you show me what ...

**Chemistry**

A small pebble is heated and placed in a foam cup calorimeter containing water at 25 °C. The water reaches a maximum temperature of 27 °C. If the pebble released 532.1 J of heat to the water, what mass (in g) of water was in the calorimeter?

**Chemistry**

If 82.4 g of cold water (initially at 22 °C) is mixed in an insulated container with 96 g of hot water (initially at 88 °C), what will be the final temperature of the water in °C?

**Calculus**

if the work required to stretch a spring 1 ft beyond its natural length is 12 ft-b, how much work is needed to stretch 9 inches beyond its natural length?

**Math**

A ball is thrown downward from the top of a 100-foot building with an initial velocity of 14 feet per second. The height of the ball h after t seconds is given by the equation h=-16t^2-14t+100. How long after the ball is thrown will it strike the ground?

**Algebra**

How can I solve 1/2x+1/x=-12?

**Chemistry**

. 0.1M Urea

**physics**

A weight oscillates in a vertical motion according to the position function y(t)=-5cos t. Assuming t>=0 (greater than or equal to), when will the acceleration of the weight be zero for the first time?

**math**

Thomas bought a 3-foot sandwich for his .Hew figured out that each guest can have 1 1/2 inches of the sandwich . HOW MANY guest does Thomas have.

**algebra**

FOR CA STUDENTS!!! 1. A 2. B 3. D 4. D 5. A

**Consumer Math**

I am purchasing a house for $235,000 and have excellent credit. If I pay $1,678.93 at the end of the first month, how much is applied to the principal balance?

**algebra**

Here are the answers for the whole QC for CA students. 1. C 2. A 3. no 4. c 5. A

**Science**

One gram of platinum has 3.09 × 1021 atoms, and each platinum atom has 78 electrons. How many electrons are contained in 4.00 g of platinum? The elemental charge is 1.6 × 10−19 C. Answer in units of electrons

**Algebra II**

Suppose that the profit, p, for selling bumper stickers is given by p(x) = 0.1x2 + 8x - 50. What is the minimum number of bumper stickers that must be sold to make a profit? a. 6 c. 10 b. 2 d. 15

**algebra**

Yes ashley

**Math**

sally bakes two cakes, a square and a circle. the length of the side of the square cakes is 8 inches. find the perimeter of the cake (the cake is in the shape of hearth )

**SCIENCE HELP ASAP! :)**

5 is a. 7 is d. 10 is a.

**Physics**

1. Two points in a plane have polar coordinates (2.5 m, 30 degrees) and (3.8 m, 120 deg). Determine (a) the cartesian coordinates of both points and (b) the distance between the points. 2. Vector A has magnitude 29 units and points along +y. When vector B is added to the ...

**Math**

3 similar shirts and 4 similar jackets cost $360. 1 such shirt and 3 such jackets cost $220. Find the cost of each shirt.

**Calculus**

Line l is tangent to the graph of y= x - x²/500 at point Q & it crosses the y-axis at (0, 20) a). Find the x-coordinate of point Q b. Write an equation for line l c) Suppose the graph of y=x-x^2/500, where x and y are measured in feet, represents a hill. There is a 50-...

**chem**

How do I calculate the rate of a reaction of a substance using the slope of the lines and stoichiometry of the reactions in moles/sec. I also know that the molarity of that substance.

**Calculus**

The position of a function of a moving particle is s(t)=5+4t-t^2 for 0<t<10 where s is in meters and t is measured in seconds. What is the maximum speed in m/sec of the particle on the interval [0,10]?

**Calculus**

Let f be the function defined by f(x)=x^3 + x. If g(x)= the inverse of f(x), and g(2)=1, what is the value of g'(2)?

**math**

Find the altitude of an isosceles triangle whose base is 8 cm and whose legs are 5 cm?

**chemistry**

Three part question Two students each measured the density of a quartz sample three times: Student A Student B 1. 3.20g/mL 2.82g/mL 2. 2.58g/mL 2.48g/mL 3. 2.10g/mL 2.59g/mL mean 2.63g/mL 2.63 g/mL a. which student measured density with the greatest precision? explain your ...

**chemistry**

The directions state "weigh about 5 grams of sodium chloride". Give minimum and maximum amounts of sodium chloride that would satisfy these instructions.

**Physics**

A car is speeding up in the forward direction on a level road. a. The frictional force acting from the road on the tires is pointed forward. b. The frictional force acting from the road on the tires is pointed backward. c. There is not enough information to determine the ...

**Spanish**

Tienes

**Calculus**

Thank you!

**Calculus**

Let f be the function given by f(x)= 2x/(sqrt(x^2 +x +1)) c. Write an equation for each horizontal asymptote of the graph of f. d. Find the range of f. Use f'(x) to justify your answer.

**Math**

Jody deposited $65 into her savings account. The next day, she withdrew $24. how much of her deposit remains in the account?

**Calculus**

Let g and h be any two twice-differentiable functions that are defined for all real numbers and that satisfy the following properties for all x: I) (g(x))^2 + (h(x))^2=1 ii) g'(x)= (h(x))^2 iii) h(x)>0 iv) g(0)=0 a)Justify that h'(x)=-g(x)h(x) for all x b) Justify ...

**English**

I have an art presentation and I need to find a piece of literature written around late 1800s to early 1900s to relate to my art (The Brooklyn Bridge photograph- Walker Evans). It'll probably need to be industrialization related. Thanks.

**Math**

2 5/8 divided by 7= Answer in simplest form

**science**

Why did Charles Darwin talk about pigeons (how breeders produced many shapes, sizes, and colors of pigeons, all starting from a wild pigeon) in his book On the Origin of Species?

**PHYSICS**

A crate is pushed horizontally with a force. The acceleration of gravity is 9.8 m/s2 . Calculate the acceleration of the crate. Answer in units of m/s2 1570 N 198 kg μ = 0.44

**physics**

A 1900 kg car moves along a horizontal road at speed v0 = 26.4 m/s. The road is wet, so the static friction coefficient between the tires and the road is only μs = 0.17 and the kinetic friction coefficient is even lower, μk = 0.119. The acceleration of gravity is 9.8...

**geometry**

A diameter of a circle is perpendicular to a chord whose length is 12 inches. If the length of the shorter segment of the diameter is 4 inches, what is the length of the longer segment of the diameter?

**geometry**

A diameter of a circle is perpendicular to a chord whose length is 12 inches. If the length of the shorter segment of the diameter is 4 inches, what is the length of the longer segment of the diameter?

**geometry**

A diameter of a circle is perpendicular to a chord whose length is 12 inches. If the length of the shorter segment of the diameter is 4 inches, what is the length of the longer segment of the diameter?

**geometry**

Two secant segments are drawn to a circle from a point outside the circle. The external segment of the first secant segment is 8 centimeters and its internal segment is 6 centimeters. If the entire length of the second secant segment is 28 centimeters, what is the length of ...

**geometry**

Two secant segments are drawn to a circle from a point outside the circle. The external segment of the first secant segment is 8 centimeters and its internal segment is 6 centimeters. If the entire length of the second secant segment is 28 centimeters, what is the length of ...

**Math**

12; 3/12 is reduced down to 1/4

**Math**

56

**math**

a. n/16

**Physics**

Calculate the water pressure at the bottom of the 100-m-high water tower

**Physics**

How much force is needed to hold a nearly weightless but rigid 1-L carton beneath the surface of water?

**Physics**

A certain spring stretches 5.8cm when a load of 38N is suspended from it. How much will the spring stretch if 48N is suspended from it (and it doesn't reach its elastic limit)?