# erica

Popular questions and responses by erica-
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## History

In which world regions or countries was the Seven Years’ War fought? a.)Australia, South America, China b.)North America, Western Europe, India c.)North Africa, Mexico, Japan d.)Scandinavia, Middle East, Afghanistan I think it is B

*asked on July 2, 2020* -
## Mathematics

The segment shown is half of AB, where B (-5,1) is one endpoint of the segment and M (-3,3) is the midpoint of the segment. What are the coordinates of point A

*asked on June 5, 2020* -
## 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* -
## 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* -
## 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* -
## Physics please i really need help

Suppose a car is traveling at +23.7 m/s, and the driver sees a traffic light turn red. After 0.427 s has elapsed (the reaction time), the driver applies the brakes, and the car decelerates at 9.00 m/s2. What is the stopping distance of the car, as measured

*asked on February 1, 2016* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## Calc

If dy/dx = x²y², then d²y/dx² = ?

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

Convert 1.01 x 10-8 seconds to nanoseconds

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

a small farm field is a square measuring 340 ft on a side. what is the perimeter of the field?

*asked on July 26, 2013* -
## 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* -
## math

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

*asked on August 30, 2018* -
## 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* -
## weber state university

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

*asked on April 11, 2013* -
## 11th grade

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

*asked on September 18, 2008* -
## 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* -
## Differential Equations (Another) Cont.

For the following initial value problem: dy/dt=1/((y+1)(t-2)) a)Find a formula for the solution. b) State the domain of definition of the solution. c) Describe what happens to the solution as it approaches the limit of its domain of definition. Why can't

*asked on January 31, 2013* -
## Math

The charges on a monthly water bill came to $0.86 per cubic meter of water used, plus a service charge of $4.49. Last month Jeremy's water bill came to $69.85, how many cubic meters of water had he used?

*asked on January 25, 2013* -
## Algebra 2

Find the value of c that makes the expression a perfect square trinomial. Then write the expression as the square of a binomial. I didn't really understand what that meant. x^2-23x+c x^2-(2/7)x+c

*asked on December 5, 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* -
## 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* -
## Managarial Finance

"Stephenson Real Estate Company was founded 25 years ago by the current CEO, Robert Stephenson. The company purchases real estate, including land and buildings, and rents the property to tenants. The company has shown a profit every year for the past 18

*asked on October 8, 2012* -
## 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* -
## 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* -
## Algebra 2

From 1990 to 1994, the mail order sales of health products in the United States can be modeled by S = 10t 3 + 115t 2 + 25t + 2505 where S is the sales (in millions of dollars) and t is the number of years since 1990. In what year were about $3885 million

*asked on December 30, 2011* -
## 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* -
## 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* -
## 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* -
## 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

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* -
## ODE Piecewise

Solve the piecewise linear ODE, y' - y = f(x), y(0) = 1, where f(x) = 1 when 0 \le x \le 1 and f(x) = -1 when x > 1. What is y(2)? Round to the nearest tenth. I stated and got y'-y= ce^x , but wasn't really sure if that was right so I didn't know where to

*asked on September 23, 2016* -
## chemistry

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

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

Imagine a giant dry-cleaner's bag full of air at a temperature of -31 floating like a balloon with a string hanging from it 15 above the ground. Estimate what its temperature would be if you were able to yank it suddenly back to Earth's surface.

*asked on May 2, 2013* -
## 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* -
## Calculus

Suppose that you follow the size of a population over time. When you plot the size of the population versus time on a semilog plot (i.e., the horizontal axis, representing time, is on a linear scale, whereas the vertical axis, representing the size of the

*asked on October 30, 2011* -
## 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* -
## 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* -
## 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* -
## 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* -
## Calc

Locate any relative extrema and inflection points. y = (ln x)/x

*asked on December 2, 2010* -
## Psychology

This is a homework assignment for my Psychology course on Memory and learning. Find a Movie/video clip (1-3 mins)that demonstrate a concept / phenomenom relevant to learning and memory? My prof used Matrix (what we see is just our neuron firing) and Bourne

*asked on March 12, 2009* -
## Pre calc

How do you write a quadratic equation in standard form for a given set of zeros?

*asked on August 2, 2008* -
## math

robert bought a used car for $1,500.00 if the sales tax is 5% what is the total that he paid?

*asked on February 12, 2008* -
## 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* -
## 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* -
## Trigonometry

Find the remaining trigonometric values if sin=-3/5 and theta terminates in Quadrent four. I'm not sure what they're asking

*asked on February 1, 2017* -
## Cal 3

Find critical points for f(x,y)= x^3+y^3-15x^2-6xy+18y^2+39x+138y I know you first take the partial derivative of x and y, but I am not sure where to go from there.

*asked on December 6, 2016* -
## Math

The figure below are similar (their rectangles) find The value of x. Skinny rectangle has 2 on the top, and it has 4 on the side. Bigger rectangle it's side ways, it has 8 on the top and x on the side

*asked on April 4, 2016* -
## Physics HELPPP

(0 m/s)^2 - (23.7 m/s)^2 divided by 2(9.00 m/s)^2 ?

*asked on February 1, 2016* -
## Math 221

what is 13/15 divided by 7/10

*asked on July 13, 2014* -
## Differential eqns

a) Sketch the phase line for the differential equation dy/dt=1/((y-2)(y+1)) and discuss the behavior of the solution with initial condition y(0)=1/2 b) Apply analytic techniques to the initial-value problem dy/dt=1/((y-2)(y+1))), y(0)=1/2 and compare your

*asked on February 3, 2013* -
## 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* -
## 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* -
## Statistics

Suppose that people's heights (in centimeters) are normally distributed, with a mean of 165 and a standard deviation of 6. We find the heights of 100 people. (a) How many would you expect to be between 157 and 173 cm tall? (b) How many would you expect to

*asked on March 14, 2012* -
## 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* -
## 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

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

A rectangle is to be inscribed in a semicircle of radius 8, with one side lying on the diameter of the circle. What is the maximum possible area of the rectangle?

*asked on February 22, 2011* -
## Calc

Find the arc length of the graph of the function over the indicated interval. y = (x⁵/10) - (1/(6x³)) , [1,20] Thank you so much!!

*asked on February 6, 2011* -
## Calc

How do you integrate sin²x?

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

The slope of a curve at each point (x,y) is given by 4x - 1. Which of the following is an equation for this curve if it passes through the point (-2,3)? A) y=4x²-x-15 B) y=x²-4x-9 C) y=2x²-x-7 D) y=2x²-x E) y=2x²-x+7

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

A group of 56 randomly selected students have a mean score of 30.8 and a standard deviation of ó = 4.5 on a placement test. Find a 95% confidence interval for the mean score, ì, of all students taking the test.

*asked on November 1, 2010* -
## 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* -
## math Thanks to everyone for the help it's needed!

what would be the radius of a circle with a diameter of 8 inches?

*asked on February 12, 2008* -
## Social studies

what is the function or purpose of public radio and television in a democratic society

*asked on April 15, 2020* -
## 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* -
## Introduction to computers

What are the steps to choosing the right computer to purchase? What are some of the choices within each step?

*asked on May 16, 2018* -
## math

A card is selected from a deck. Find the following probabilities. A standard deck of cards has 52 Cards. There are 13 values and 4 suits. Suits are Spades, Clubs, Diamonds and Hearts. Each suit has 13 cards. There are 3 face cards Jack, Queen, and King. a

*asked on July 3, 2017* -
## 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* -
## Physics

A car goes North at 55mi/hr for 1.3 hrs. It then goes East at 65mi/hr for 45 min. What is the total distance travelled, total displacement,average speed and average velocity of the car?

*asked on September 9, 2016* -
## 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* -
## Physics

The initial velocity and acceleration of four moving objects at a given instant in time are given in the following table. Determine the final speed of each of the objects, assuming that the time elapsed since t = 0 s is 2.0 s. Initial Velocity (a) +12 m/s

*asked on February 1, 2016* -
## chemistry

Convert 15 ºF to degrees K. (Just type the number with correct sig figs, do worry about finding the degree symbol)

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

From the reaction below, calculate the free energy of formation for CH4(g) at 25°C, if ΔGfo(C8H8(g)) is 214.417 kJ/mol. 8CH4(g) ↔ C8H8(g) + 12H2(g) ΔGo = 620.735 kJ/mol I don't understand what equation to use. I thought it was dGfo-dGo but that

*asked on May 3, 2014* -
## 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* -
## 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* -
## Ethics in Criminal Justice

The power to make choices and engage in actions that originate with ourselves is referred to as: A. Free will B. Objectivism. C. Determination. D. Predetermination.

*asked on April 13, 2014* -
## algebra

A newspaper carrier has $4.00 in change. He has two more quarters than dimes but five times as many nickels as quarters. How many of coins of each type does he have. This is what I got so far and then I get lost. dimes = x quarters = x+2 nickels = 5(x+2)

*asked on February 12, 2014* -
## Physics

You are holding a bulletin board weighing 7.01 N in place against a wall while your friend secures it to the wall. To keep it from slipping, you apply a force perpendicular to the bulletin board, pressing it directly into the wall. How large must this

*asked on October 2, 2013* -
## math

Select a real life object (tree flagpole ect) or distance that cannot be measured directly. Describe how to measure an object or distance by right-angled trigonometry using methods such as SOH CAH TOA or the pythogrorean theorem. Organize all the data you

*asked on August 14, 2012* -
## 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* -
## Calc

Solve: du/dt = (sin t) / (u^2 + 1) So far I got: arctan u = -ln |csc t + cot t| + C I'm not sure where to go from there. Thank you so much for the help!

*asked on October 31, 2011* -
## Statistics

The production process of computer parts uses two machines one old & one new. If the old machine is used the probability that the defected part is produced is .13 if the new machine is used the probability that the defective part is produced is .04.

*asked on October 12, 2011* -
## Chem

Calculate the amount (in moles) of H₂O in 2.00g of Na₂CO₃ ⋅ 10H₂O. Thanks so much!!

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

Journalize the following transactions -Received cash from investment made by owner,$15000. Received cach providing accounting services, $8000. Billed customers on account for providing services, $4000. Paid Advertising expense 400. Received cash from

*asked on September 20, 2011* -
## Science

What is the pressure at the bottom of a tube of mercury that is 0.2 m deep? An elephant with a mass of 1000 kg stands on a circus platform that weighs 50 kg. The area of the bottom of the platform is 1.25 m². How much pressure is exerted on the floor

*asked on September 15, 2011*