# erica

Most popular questions and responses by erica-
## Calc

The number of bacteria in a culture is increasing according to the law of exponential growth. There are 125 bacteria in the culture after 2 hours and 350 bacteria after 4 hours. a) Find the initial population. b) Write an exponential growth model for the

*asked on January 6, 2011* -
## science

which of the following is true about photosynthesis

*asked on October 6, 2016* -
## Physics (Help!)

You throw a glove straight upward to celebrate a victory. Its initial kinetic energy is K and it reaches a maximum height H. What is the kinetic energy of the glove when it is at the height H/2?

*asked on January 9, 2011* -
## Calc

Let f be the function given by f(x) = tan x and let g be the function given by g(x) = x^2. At what value of x in the interval 0≤x≤π do the graphs of f and g have parallel tangent lines?

*asked on January 2, 2011* -
## Math

A rocket is launched from ground level with an initial vertical velocity (v0) of 176 ft/s. After how many seconds will the rocket hit the ground? (Hint: h(t) = -16t2 + v0t + h0)

*asked on November 26, 2012* -
## Pre algebra

Please help I’m struggling with how to find the percent of change each decade and how to predict a future price. I can’t find any examples of this lesson for help Directions: You probably see them in the news all the time—predictions about prices,

*asked on December 8, 2017* -
## Chemistry

I need help please I am so confused. How much dry solute would you take to prepare each of the following solutions from the dry solute and the solvent? I know the MM of KCl is 74.55 107g of 0.535m KCl

*asked on September 18, 2012* -
## Physics

A 50.0 g silver spoon at 20.0 degrees Celsius is placed in a cup of coffee at 90.0 degrees C. How much heat does the spoon absorb from the coffee to reach a temp. of 89.0 degrees C? Rememeber this equation. It, or a slight modification of it, will work all

*asked on November 21, 2006* -
## Calc

Use differentials to approximate the change in the volume of a cube when the side is decreased from 8 to 7.99 cm. (in cm^3) Thank you so much!!

*asked on April 25, 2011* -
## physics

How much heat is necessary to change 500g of ice at-10 celsius to water at 20 celsius?

*asked on October 15, 2012* -
## global history

the wealth that enabled the Italian city-states to lead in the development of Renaissance arts was derived mainly from? a)the quantities of gold and silver brought back to Italian explorers b)concentration of riches in the hands of the king and his court

*asked on May 31, 2011* -
## chemistry

A tank holds 52.9 cm3 of water. What is the volume in in3? (2.54 cm=1 in, Remember significant figures, but this answer does not need units, since the answer must be in in3)

*asked on September 14, 2015* -
## Physics

A stationary billiard ball, mass 0.17 kg, is struck by an identical ball moving at 2.7 m/s. After the collision, the second ball moves off at 60° to the left of its original direction. The stationary ball moves off at 30° to the right of the moving

*asked on January 20, 2010* -
## stats

A company with a large fleet of cars found that the emissions systems of 18 out of the 65 randomly selected cars they tested failed to meet pollution control guidelines. Is this strong evidence that more than 20% of the fleet might be out of compliance?

*asked on May 11, 2011* -
## American Government

Why do presidents prefer federal judges who tend to agree with their views?

*asked on January 4, 2017* -
## Differential Equations

The velocity v of a freefalling skydiver is well modeled by the differential equation m*dv/dt=mg-kv^2 where m is the mass of the skydiver, g is the gravitational constant, and k is the drag coefficient determined by the position of the driver during the

*asked on January 24, 2013* -
## Pre-Calculus

The formula D= 5e ^-0.4h can be used to find the number of milligrams D of a certain drug that is in a patient's bloodstream h hours after the drug has been administered. When the number of milligrams reaches 2, the drug is to be administered again. WHat

*asked on October 10, 2006* -
## weber state university

CH2=CH-CH2CH3+H2O What is the product of the reaction above

*asked on April 11, 2013* -
## Finance

Determine the annual net cost of this checking account? Annual interest of 2.5% paid if balance exceeds $750, $8 monthly fee if account falls below minimum balance, average balance $815, account falls below $750 during 4 months. Is my answer correct? 815 *

*asked on August 8, 2013* -
## Physics 1

The drawing shows three particles far away from any other objects and located on a straight line. Particle B is located in the middle of particles A and C. The distance between particles A and B is 0.500 m. The distance between particles B and C is 0.250

*asked on February 19, 2014* -
## Science-Physics

You push a 67 kg box across a floor where the coefficient of kinetic friction is uk = .55. The force you exert is horizontal. (a) How much power is needed to push the box at a speed of .50 m/s? (b) How much work do you do if you push the box for 35 s?

*asked on January 9, 2011* -
## Calc

How do you integrate sin²x?

*asked on February 2, 2011* -
## physics

A sample of blood is placed in a centrifuge of radius 20.0 cm. The mass of a red blood cell is 3.0 10-16 kg, and the magnitude of the force acting on it as it settles out of the plasma is 4.0 10-11 N. At how many revolutions per second should the

*asked on October 18, 2010* -
## chemistry

A student measure 9.43 mL of an unknown liquid in a graduated cylinder. The mass of the empty cylinder is 34.670 g, and the mass of the cylinder and liquid is 44.197 g. What is the density of the unknown liquid? (remember significant figures and units in

*asked on September 14, 2015* -
## Chem

Epsom salts consist of magnesium sulfate heptahydrate. Write its formula. a) How many atoms of oxygen are in 5.15g of Epsom salts? b) How many formula units of the compound are present in 5.15g? c) How many moles of water molecules are in 5.15 g of Epsom

*asked on October 7, 2011* -
## Chemistry

A mixture of gases at 760.0 torr contains 35.0% nitrogen, 22.0% oxygen , and 43.0% carbon dioxide by volume. What is the pressure of the carbon dioxide gas in torr?

*asked on August 19, 2011* -
## Math

Nico was stunned when he opened the mail. Here was a check for $322.50! This was the interest he earned on his investment. One year ago Nico had been given $5,000. His parents made him put it in the bank and save it for college, but they said he could keep

*asked on April 16, 2012* -
## Chemistry

The density of aluminum is 2.70 g/ml. What is the mass of a cube of Al that measures 2.20 cm on each side?(remember significant figures and to include the units of g in your answer, remember that 1 ml=1 cm3)

*asked on September 14, 2015* -
## math

What is a generalization for this set of polygons: square, hexagon and a pentagon

*asked on February 1, 2010* -
## chemistry

at 327 degrees C, the equilibrium concentrations are [CH3OH]=0.15M, [CO]=0.24M, and [H2]=1.1M for the reaction: CH3OH(g)CO(g)+2H2(g) Calculate Kp at this temperature

*asked on February 16, 2011* -
## Physics

A bag of sugar weighs 4.00 lb on Earth. What would it weigh in newtons on the Moon, where the free-fall acceleration is one-sixth that on Earth? 1 N Repeat for Jupiter, where g is 2.64 times that on Earth. 2 N Find the mass of the bag of sugar in kilograms

*asked on September 16, 2010* -
## reading

the reason the test questions and answers is up there because its all wrong answers on purpose for cheaters. when i first started i passed two test by myself. then the last three test try to cheat to use the answers and failed three test then retook them

*asked on July 9, 2012* -
## Calc

If f(x) = e^(sin x), how many zeros does f '(x) have on the closed interval [0, 2π]?

*asked on January 2, 2011* -
## Psychology

Classical Conditioning. 1)Terell feels ill every time he sees a Wendy's restaurant sign. Two weeks ago while on his lunch break, he went to Wendy's and ate a chicken sandwich. He was not aware that the chicken was spoiled. a. Name the Unconditioned

*asked on July 12, 2015* -
## Calc

A body of an unknown temperature was placed in a room that was held at 30°F. After 10 minutes, the body's temperature was 0°F, and 20 minutes after the body was placed in the room the body's temperature was 15°F. Estimate the body's initial temperature.

*asked on January 6, 2011* -
## math

A farmer is installing a fence. The coordinates of the vertices of the fence are A(2,2), B(2,6), C(8,6), D(8,2). If each grid square has length of 9 yards, how much wire is needed for the fence?

*asked on May 12, 2015* -
## alg

An amplifier has an input power of 5 mW. The output power is 100 mW. What is the decibel gain to the nearest decibel?

*asked on June 28, 2012* -
## Math

The population of humorville is 8,500 people. In this town, jokes travel fast. In one hour, each person who hears a joke tells three other people who have not heard it, and tells no one else. Last Friday, a visitor from out of town told the police chief a

*asked on March 19, 2012* -
## physical science

you are standing on a street corner, and you hear a fire truck approaching. does the pitch of the siren stay constant, increase, or decrease as it approaches you? does the pitch of the siren stay constant, increase, or decrease as it moves away?

*asked on May 23, 2011* -
## science

an electron in a one-dimensional box requires photons with a wavelength 8080 nm to excite it from the n=2 energy level to the n=3 energy level. calculate the length of the box

*asked on December 14, 2010* -
## Psychology

Classical Conditioning. 2. Pat feels fear whenever she sees snow. Not too long ago, she got into a car accident on a snowy road. a. Name the unconditioned stimulus(US): Car accident b. Name the conditioned stimulus(CS): Seeing snow c. Name the

*asked on July 12, 2015* -
## Calculus

A 20m ladder is leaning against a wall. Top of ladder is sliding down at 3m per second and the bottom is sliding away from the wall at 4m per second. How high is the top of the ladder and far is the bottom of the ladder from the wall.

*asked on July 23, 2016* -
## Ethics in Criminal Justice

The correlativity of rights and duties mean that: A. moral duties override moral rights. B. moral rights override moral duties. C. the existence of moral rights implies duties by which other must abide. D. None of the above. I think the answer is A but not

*asked on May 10, 2014* -
## 6th grade

If today is Tuesday, what integer stands for last Sunday?

*asked on May 4, 2010* -
## math

the dome over a town hall has a parabolic shape. the dome measures 48 m across and rises 12m at the centre. A vertical column needs to be attached to the dome at a point that is 4m away from its rim. How tall is the dome at this point? Also, what is the

*asked on August 31, 2012* -
## Calc

If dy/dx = x²y², then d²y/dx² = ?

*asked on January 2, 2011* -
## Chemistry

Calculate the change in enthalpy produced by dissolving 14.3 g of NaOH in 65.0 g of water if the temperature increases 49.1°C and the specific heat of water is 4.18 J/g°C Do I have to use the 14.3g of NaOH?

*asked on February 7, 2018* -
## Ethics in Criminal Justice

Which of the following might help us develop open-mindedness and the virtue of tolerance? A. Recognizing that people have free will. B. Recognizing that moral norms can and often do vary by time and place. C. Developing our own sense of egoism. D. All of

*asked on April 21, 2014* -
## math

a popular tourist attraction in ottawa is the Peace tower, which rises from the Center Block of the Parliment buildings. Describe at least one method that you could use to estimate the height of the tower, including the measurments you would need to make.

*asked on August 13, 2012* -
## english

What roles are played by the female characters you encountered in this unit? Describe some of these female characters, their traits, and the roles they played within the selections you read, especially considering that all of those selections had male

*asked on February 19, 2019* -
## Ethics in Criminal Justice

Engaging in lawbreaking behavior to achieve a reputation or gain status among peers would be most consistent with which of the following stages of moral development, according to Kohlberg's model? A. Punishment/Obedience B. Law and Order C. Social Contract

*asked on April 27, 2014* -
## Chemistry

large dose of vitamin C are supposed to cure the common cold. One commercial over-the-counter product consists of 500-mg tablets that are 20% by weight vitamin C. How many tablets should one take for a 1.30g dose of vitamin C?

*asked on January 20, 2012* -
## math

The student council has decided to sell t-shirts for a fundraiser. The printing company charges a $75 set-up fee plus $3 per shirt. The student council plans to sell their t-shirts for $12 per shirt. Write a function p(t) to represent the student council's

*asked on May 5, 2014* -
## 11th grade

your pet dog runs around in circles, chasing his tail. Does this mean acceleration?

*asked on September 18, 2008* -
## Science

How do clouds form, and where in canada would you expect to see certain types of clouds. What is the difference between clouds and fog? http://en.wikipedia.org/wiki/Cloud

*asked on May 20, 2007* -
## physics

lead is a soft, dense metal with a specific heat of 0.028 kcal/kg degrees C, a melting point of 328.0 degrees C and a heat of fusion of 5.5 kcal/kg. How much heat must be provided to melt a 250.0 kg sample of lead with a temperature of 20.0 degrees

*asked on November 21, 2006* -
## Probability/Distribution

A catalyst researcher states that the diameters (in microns) of the pores in a new product catalyst she has made have an exponential distribution with parameter ë = 0.25 (35 pts). (a) Determine the mean pore size. (b) Determine the standard deviation of

*asked on October 11, 2016* -
## algebra1

the problem is 5f+7 less than or equal to 22. can anyone please work this out for me and check it for me? and what i mean by checking it is like when you get the answer you check it and make sure its write.

*asked on October 1, 2013* -
## Chem

The field of nanotechnology offers some intriguing possibilities, such as the creation of fibers one atom wide. Suppose you were able to string together 1.00 mol Ag atoms, each of radius 144 pm, into one of these fibers by encapsulating them in carbon

*asked on October 8, 2011* -
## Calc

A rectangular box, with a square base and open at the top is to be constructed. If the volume of the box needs to be 108 cubic feet, what is the minimum surface area?

*asked on January 23, 2011* -
## Physics

A car's initial velocity of 13.5 m/s accelerates at a rate of 1.9 m/s^2 for 6.2 s. Then, it accelerates at a rate of -1.2 m/s^2 until it stops. 1) What is the car's maximum speed? 2) What is the total time from the start of the first acceleration until the

*asked on February 1, 2012* -
## Calc

The base of a solid is a circle of radius a, and its vertical cross sections are equilateral triangles. The volume of the solid is 10 cubic meters. Find the radius of the circle.

*asked on February 10, 2011* -
## Physics

a 1.0 metal head of a geology hammer strikes a solid rock with a velocity of 5.0 m/s. Assuming all the energy is retained by the hammer head, how much will its temperature increase? (Chead=0.11 kcal/kg degrees C) 1/2 m v^2 = mc Deltatemp solve for

*asked on November 21, 2006* -
## English

After they heard the winner announced, Greg’s friends congratulated him. Then teased him to take them out for pizza. Help with sentence structure please

*asked on March 24, 2019* -
## Probability

A drawer contains six bags numbered 1-6, respectively. Bag i contains i blue balls and 2 green balls. You roll a fair die and then pick a ball out of the bag with the number shown on the die. What is the probability that the ball is blue? Thank you!

*asked on January 27, 2012* -
## Physics

Which provides more cooling for a styrofoam cooler, one with 10 lbs of ice at 0 degrees C or one with 10 lbs of ice water at 0 degrees C. Explain. qice=mass*heat of fusion. qH2O=mass*specific heat x delta T However, you aren't given a two temperatures;

*asked on November 21, 2006* -
## chemistry

Convert 1.01 x 10-8 seconds to nanoseconds

*asked on September 14, 2015* -
## Physics

Spent steam from an electric generating plant leaves the turbines at 120.0 degrees Celsius and is cooled to 90.0 degrees Celsuius liquid water by water from a cooling tower in a heat exchanger. How much heat is removed by the cooling tower water for each

*asked on November 21, 2006* -
## Math

Tino conducted a survey of all the eighth graders in his school for his math project. He asked each student how much he or she spent on school supplies at the beginning of the year (rounded to the nearest dollar). He also calculated the average amount

*asked on May 8, 2012* -
## Math

the design below grows each day, as shown. if the pattern continues to grow like this, how many tiles will there be in the design on the tenth day? on the fiftieth day? Day 1 1 tile Day 2 5 tiles Day 3 13 tiles

*asked on March 5, 2012* -
## Math

I snap my fingers now. in one second, i snap them again. I wait two seconds and snap them a third time. I wait four seconds before snapping them again. then i wait eight seconds, then sixteen, and the pattern continues on. the interval between snaps

*asked on March 13, 2012* -
## Algebra 2

On some tubes of caulking, the diameter of the circular nozzle opening can be adjusted to produce lines of varying thickness. The table shows the length l of caulking obtained from a tube when the nozzle opening has diameter d and cross-sectional area A.

*asked on March 3, 2012* -
## Ethics in Criminal Justice

The correlativity of rights and duties means that: A. moral duties override moral rights. B. moral rights override moral duties. C. the existence of moral rights implies duties by which others must abide. D. None of the above. I think it's B. Am I right?

*asked on May 8, 2014* -
## Differential Equations

Consider the differential equation: dy/dt=y/t^2 a) Show that the constant function y1(t)=0 is a solution. b)Show that there are infinitely many other functions that satisfy the differential equation, that agree with this solution when t0 [Hint: you need to

*asked on January 31, 2013* -
## Ethics in Criminal Justice

The argument that aiding or assisting others might be degrading to them, implying that they are incapable of helping themselves, is an argument commonly used to support: A. Qualitative varieties of utilitarianism. B. Hedonism. C. Ethical egoism D. Plea

*asked on May 3, 2014* -
## FREE BODY DIAGRAM calculus

A car is traveling north towards an intersection at 60mph at the same time a truck is headed east toward the same intersection at 45mph. Find the rate of change of the distance between the car and truck when the car is 3 miles south of the intersection and

*asked on October 7, 2012* -
## Chemistry

The crystal structure of lithium sulfide (Li2S) is pictured here. The length of the unit cell is 5.88 x 10^2. For this structure, determine: a)the coordination number of Li and S b) the number of formula nunits in the unit cell c) the density of Li2S

*asked on April 15, 2009* -
## Trig

A jet is 115 mi east and 88.3 i north of Niagara Falls. What is its displacement from Niagara Falls?

*asked on December 1, 2014* -
## Chemistry

2NaOH+2Al+2H2O --> 2NaAlO2+3H2 here is the reaction. If i am trying to find the mass of hydrogen produced and i am trying to convert .95 moles Al to moles H, which number from the reaction do I use for H when converting from moles to moles? Do I 6 because

*asked on March 9, 2012* -
## Calc

Use differentials to approximate the change in the volume of a cube when the side is decreased from 8 to 7.99 cm. (in cm^3) Thank you so much!!

*asked on April 25, 2011* -
## Pre-Calculus

The logistic growth model p(t)=0.90/1+3.5e^-0.339t relates the proportion of new personal computers sold @ Best Buy that have Intel's latest coprecessor t months after it has been introduced. a) what proportion of new personal computers sold @ Best Buy

*asked on October 19, 2006* -
## Pre-Calculus

The period T (in seconds) of a simple pendulum is a function of its length l (in feet), given by T(l) = 2pi sq root of l/g, where g = 32.2 feet per second per seconds is the acceleration of gravity. Express the length l as a function of the period T. If

*asked on October 5, 2006* -
## Ethics in Criminal Justice

If we eliminate free will completely, we would also be eliminating: A. the possibility of genetic bases for human behavior. B. The value of modern science. C. Moral responsibility. D. Excuses for criminal conduct.

*asked on April 13, 2014* -
## Pre Calculs

The pH of a chemical solution is given by the formula pH = -log10 [H+] where [H+] is the concentration of hydrogen ions in moles per liter. Values of pH range from 0 (acidic) to 14 (alkaline). (a) what is the pH of the solution for which [H+] is 0.1? (b)

*asked on October 10, 2006* -
## calculus

A fence 8 feet tall stands on level ground and runs parallel to a tall building. If the fence is 1 foot from the building, find the shortest ladder that will extend from the ground over the fence to the wall of the building.

*asked on October 11, 2012* -
## psychology

Today, most psychologists take ____ approach to human development. a nativist an empiricist a dualist an interactionist

*asked on November 2, 2010* -
## chemistry

How many inches are in 2.41 m? (2.54 cm = 1 inch, remember significant figures and units)

*asked on September 14, 2015* -
## Binomial

Independent samples of n1 = 400 and n2= 400 observations were selected from binomial populations 1 and 2, and x1 = 100 and x2 = 127 successes were observed. What is the best point estimator for the difference ( p1-p2) in the two binomial proportions? a.

*asked on November 24, 2010* -
## pre-calculus

the spread of oil leaking from a tanker is in the shape of a circle. If the radius r (in feet) of the spread after t hours is r(t)= 200 square root of t, find the area A of the oil slick as a function of the time t. You know that the area of a circle is

*asked on October 3, 2006* -
## math

How can you use an equation to make a prediction from a pattern?

*asked on August 30, 2018* -
## Probability

Automated chemical synthesis of DNA has made it possible to custom-order moderate length DNA sequences from commercial suppliers. Assume that a single nucleotide weighs about 5.6 X 10^-22 grams and that there are four kinds of nucleotides. If you wish to

*asked on January 16, 2012* -
## calc

The rate that an object cools is directly proportional to the difference between its temperature ( in Kelvins) at that time and the surrounding temperature (in Kelvins). If an object is initially at 35K, and the surrounding temperature remains constant at

*asked on April 25, 2011* -
## Calc

The amount A(t) of a certain item produced in a factory is given by A(t) = 4000 + 48(t - 3) - 4(t - 3)³ where t is the number of hours of production since the beginning of the workday at 8:00 am. At what times is the rate of production increasing most

*asked on January 2, 2011* -
## Chemistry

The crystal structure of lithium sulfide (Li2S) is pictured here. The length of the unit cell is 5.88 x 10^2. For this structure, determine: (I could not paste the actual picture from the assignment here, but if you go to Google Image and type in "crystal

*asked on April 14, 2009* -
## Pre-Calculus

The monthly revenue acheived by selling x boxes of candy is calculated to be x(5-0.05x)dollars. The wholesale cost of each box of candy is $1.50. How many boxes must be sold each month to achieve a profit of at least $60. Can someone please let me know how

*asked on September 19, 2006* -
## Math 221

what is 13/15 divided by 7/10

*asked on July 13, 2014* -
## Calc

A particle moves along a path described by x=cos³t and y=sin³t. The distance that the particle travels along the path from t=0 to t=π/2 is... Thank you!

*asked on April 25, 2011* -
## Social studies

which of the following best illustrates how a president can use the news media to reach the largest segment of the public? 1. hold a state dinner for foreign dignitaries 2. hold a conference with cabinet members 3. meet with heads of congressional

*asked on March 10, 2019* -
## computers

Open your text editor (Notepad) and type the following code: My sample HTML page This is an HTML page

*asked on February 28, 2019* -
## Math

At Irv's Rental Shop, Irv rents all kinds of cycles: unicycles, tandem bikes, regular bikes, and even tricycles for little kids. He parks all the cycles in front of his shop with a helmet for each rider strapped to the cycles. This morning Irv counted 57

*asked on May 15, 2012*