# zach

Popular questions and responses by zach-
## Physics

In a hydroelectric dam, water falls 26.0 m and then spins a turbine to generate electricity. What is ∆U of 1.0 kg of water? Suppose the dam is 80% efficient at converting the water's potential energy to electrical energy. How many kilograms of water must

*asked on November 30, 2009* -
## Chemistry

Calculate the DELTA H(rxn), DELTA S(rxn), DELTA S(universe), DELTA G(rxn). For each system below indicate whether DELTA S and DELTA H are positive or negative. Then indicate if the reaction is entropy driven, enthalpy driven or neither. C3H8(g) + 2O2(g) =>

*asked on September 19, 2008* -
## Chemistry

What is the balanced equation for copper (II) sulfate pentahydrate and potassium oxalate monohydrate?

*asked on July 6, 2012* -
## algebra 1

Which of the following equations has the given solution set? Solution set: Ø

*asked on July 13, 2013* -
## physics

Your car is stuck in a mud hole. You are alone but you have a long strong rope. having studied physics you tie the rope tautly to a telephone pole and pull on it sideways at the midpoint as shown. Find the force exerted by the rope on the car when the anle

*asked on November 23, 2015* -
## Math (algebra)

Matt has to bake muffins. He uses x eggs for each 200 grams of flour. If he has to use 900 grams of flour how many eggs will he use? I have to set this up as an algebra problem. I am stuck. Our class is just learning this and I don't understand.

*asked on January 11, 2012* -
## Math

What is the annual interest rate if $1600 is invested for 6yrs. and 456 in intrest is earned

*asked on November 9, 2011* -
## Science

Which of the following best explains which planet is farther from the sun? Planet W, because gravity is inversely proportional to the square of distance Planet X, because gravity is inversely proportional to the square of distance Planet X, because the sun

*asked on April 10, 2019* -
## Math

Find the following values if: f(x) = 3x - 2 and g(x) = 4x2 + 5 c) f(-1) = d) g(-3) = e) f(5) - g(2) =

*asked on July 12, 2018* -
## Chemistry

A(n) ____ reaction is one in which oxygen reacts with another compound to form carbon dioxide, water, and heat.

*asked on January 4, 2012* -
## science

the tracks of the astronauts who landed on the moon are still there in the dust and show no signs of being worn away.this is attruted to the lack of atmosphere on the moon. which of the following best accounts for the lack of atmosphere.

*asked on November 8, 2011* -
## Math

The map of a biking trail is drawn on a coordinate grid. The trail starts at P(−3, 2) and goes to Q(1, 2). It continues from Q to R(1, −1) and then to S(8, −1). What is the total length (in units) of the biking trail? 11 13 14 16

*asked on November 27, 2017* -
## Chemistry

A sample of gas contains 0.1900 mol of HBr(g) and 9.500×10-2 mol of Cl2(g) and occupies a volume of 11.2 L. The following reaction takes place: 2HBr(g) + Cl2(g)2HCl(g) + Br2(g) Calculate the volume of the sample after the reaction takes place, assuming

*asked on October 8, 2017* -
## Math

The cost of producing x units of a product is given by C(x)=800+120x−120ln(x),x≥1. Find the minimum average cost, which is defined as C(x)/x (the total cost divided by the number of units). Minimum Average Cost =

*asked on January 24, 2017* -
## Math

Solve the inequality. Expression solution set using interval notation and graph the solution set using a number line. -15x+3

*asked on January 29, 2016* -
## Math

Solve the inequality. Expression solution set using interval notation and graph the solution set using a number line. -15x+3

*asked on January 29, 2016* -
## Physics

The 1.1 kg physics book is connected by a string to a 250 g coffee cup. The book is given a push up the slope and released with a speed of 2.9 m/s . The coefficients of friction are μs =0.50 and μk =0.20. What Distance does it travel up the slope? I drew

*asked on October 7, 2015* -
## Algebra 2

what is the positive solution of the equation 1/2x^2 -3x =5? solve by using a table or by graphing. if necessary, round your answer to the nearest hundredth.

*asked on December 8, 2014* -
## Math

A 15-g sample of radioactive iodine decays in such a way that the mass remaining after t days is given by m(t) = 15e^(−0.051t), where m(t) is measured in grams. After how many days is there only 3 g remaining?

*asked on April 22, 2013* -
## Physics

A ball swings in a vertical circle at the end of a rope 1.50 m long. When the ball is 35.9° past the lowest point on its way up, its total acceleration is (-22.5 i + 20.2 j)m/s^2. Find radial acceleration?

*asked on September 17, 2011* -
## geometry

Given the points K=(-2,1) and m(3,4), find coordinates for a point J that makes angle JKM a right angle.

*asked on September 8, 2011* -
## chemistry

PLEASE NOTE: Titration requires several steps in order to obtain exact results. The procedures described in this lab assume that you have already done the TITRATION TUTORIAL and are familiar with the technique. 1. Prepare the NaOH solution by dissolving

*asked on April 15, 2011* -
## math

Graph the linear equation. -3x + y = -6

*asked on May 5, 2010* -
## Physics

The earth rotates once per day about an axis passing through the north and south poles, an axis that is perpendicular to the plane of the equator. Assuming the earth is a sphere with a radius of 6.38 106 m, determine the speed and centripetal acceleration

*asked on March 3, 2008* -
## History

1) What was the purpose of the Treaty of Tordesillas? How did other countries respond when Portugal built a global empire? Select 3 events that led to the Spanish conquest of the Aztec Empire. Led to Spanish conquest of the Aztec Empire Caribbean colonies

*asked on April 2, 2020* -
## Science

The following table shows the period of revolution of some unknown planets of equal mass. Planet Period of Revolution W 1.9 years X 11.8 years Which of the following best explains which planet is farther from the sun? Planet W, because gravity is inversely

*asked on April 10, 2019* -
## Math

Simplify the expression. [(4^2)^2]^2

*asked on July 2, 2018* -
## physics

A golfer imparts a speed of 40.0 m/s to a ball, and it travels the maximum possible distance before landing on the green. The tee and the green are at the same elevation. (a) How much time does the ball spend in the air? (b) What is the longest "hole in

*asked on January 27, 2018* -
## Chemistry

Write a net ionic equation for the reaction that occurs when aqueous solutions of barium hydroxide and hypochlorous acid are combined.

*asked on September 24, 2017* -
## Science HELP PLS

how are earth and venus similar? how is venus different from earth? provide two similarities and two differences

*asked on February 26, 2016* -
## math

The diagonal of a rectangular storage room is 4 yards long. If its length is 2 times its width, find the dimensions of the room.

*asked on November 29, 2015* -
## Biology

What does the notation 4n = 28 tell you about how many types of chromosomes there are and how many of each type of chromosome are present in a cell? I am a little confused on how this is determined. Would it be 4 sets of chromosomes with 7 of each type of

*asked on August 24, 2013* -
## Organic Chemistry

I am trying to figure out if I am correct about the solubility of 9-fluorenone in NaOH and diethyl ether and the solubility of benzoic acid in NaOH and diethyl ether 9-fluorenone is soluble in diethyl ether because it can hydrogen bond with water so it is

*asked on February 18, 2013* -
## math

The perimeter of rectangle ABCD is 256 inches. It's length is 3 times as long as its width. Find the area of triangle ABC.

*asked on February 14, 2012* -
## science

In order for conduction to occur particles must make what?

*asked on October 26, 2010* -
## Algebra

The radius of a circle is increased by 85%. How much will the area increase in percent? Round your answer to the nearest tenth if a percent. I'm stuck on this question. Thanks -Zach

*asked on December 27, 2009* -
## Math

The perimeter of a rectangle is 34 feet and the area measures 60 square feet. What are the length and width of the rectangle? (Hint: Use the equations : perimeter = times the sum of the length and the width area = length times width)

*asked on November 21, 2009* -
## world civ

Development Indicators for Country X What does the chart suggest about Country X? Check all that apply. It is a developed country. It is a developing country. It likely has a very high HDI ranking. It likely has a medium HDI ranking. It likely has a low or

*asked on May 7, 2020* -
## History

Why did sugar plantations produce such high profits

*asked on April 2, 2020* -
## science

What is the variable x in the following hydrate formula NaCl xH2O if the mass of sodium chloride is 58g and the mass of the water is 36g

*asked on November 29, 2018* -
## physics

A 12801 kg freight train, coasting at 19 m/s, strikes a stationary 2445 kg box car. Determine the "CHANGE IN MOMENTUM" for the freight train if the freight train and the box car couple together. Hint: Draw an "IF Chart" to solve. i got -39005.01

*asked on April 9, 2018* -
## physics

A 2285 kg freight train, coasting at 13 m/s, strikes a stationary 2465 kg box car. Determine the "CHANGE IN VELOCITY" for the freight train if the freight train and the box car couple together. Hint: Draw an "IF Chart" to solve.

*asked on April 9, 2018* -
## physics

A 2285 kg freight train, coasting at 13 m/s, strikes a stationary 2465 kg box car. Determine the "CHANGE IN VELOCITY" for the freight train if the freight train and the box car couple together.

*asked on April 9, 2018* -
## physics

Bruce the Shark, is swimming very fast, at a constant velocity of 8 m/s. Bruce has a mass of 831 kg and is able to generate a force of 15 N with his tail. Calculate the pmomentum, in kg*m/s of this large shark. answer please

*asked on March 30, 2018* -
## Math. (Didn't understand please help!)

Suppose 20% of babies born are born early, 50% are born on time, and 30% are born late. A nurse uses a random-number table to find the experimental probability that of 5 births, at least 1 baby will be born early. The digits 0 and 1 represent babies born

*asked on April 11, 2017* -
## Statistics

Free Throw Freddie is an 80% free throw shooter. At the end of practice he shoots until he makes 10 shots. a) What is the probability that Freddie makes 10 in a row? b) What is the probability that Freddie needs 15 or more attempts? I understand how to do

*asked on September 11, 2016* -
## Calculus

The following equation defines y as a function of x. −5xy−3x=−6y

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

A function f is defined by the equation f(x)=4x−8. Suppose that the state variables T and Q are related by this function according to the mapping f:Q↦T. Suppose that T=3. Use the equation of the function to find the value of Q.

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

1.) when might preserved remains of an entire organism form? A.) when sediment buries the hard part of an organism B.) when an event such as a quick burial or freezing preserves an entire organism ******* C.) when minerals replace parts of an organism D.)

*asked on February 29, 2016* -
## physics

A ball is thrown straight up and reaches a maximum height of 7.16 m. What was its initial speed? The acceleration of gravity is 9.8 m/s Answer in units of m/s.

*asked on September 25, 2015* -
## College Algebra

A rectangular garden next to a building is to be fenced on three sides. Fencing for the side parallel to the building costs $60 per foot, and material for the other two sides costs $20 per foot. If $1,500 is to be spent on fencing, what are the dimensions

*asked on March 26, 2015* -
## Algebra 2

find the real solutions of each equation by graphing. 15x^4=11x^3+14x^2

*asked on February 10, 2015* -
## Algebra 2

write each function in vertex form f(x) =-2x^2 =6x + 10

*asked on December 10, 2014* -
## physics

A passenger weighing 800 N is inside an elevator weighing 25000 N that rises 30 m in exactly 1 min. How much power is needed for the elevator's trip?

*asked on March 27, 2014* -
## math

How do I find this integral using weierstrass substitution? 1/(9-4((sinx)^2))

*asked on March 1, 2013* -
## Physics

how much heat energy needed to convert 125g ice 27 deg C to 50 deg C

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

A mass-spring system has b/m = ω0/2, where b is the damping constant and ω0 the natural frequency. How does its amplitude A when driven at a frequency 12% above ω0 compare with its amplitude at resonance Ares at ω0?

*asked on November 12, 2012* -
## Science

The products of the reaction between zinc and sulfuric acid are zinc sulfate, hydrogen sulfide, and water. Balance the equation using the electron-transfer method.

*asked on November 6, 2012* -
## Chemistry

I am trying to figure out how to calculate the reaction rate. In my question the reaction rate is: 1/2x molarity of sodium thiosulfate/reaction time Then I have to compare the rates of runs 1-3 and determine the orders of the reaction. Do I only find the

*asked on October 1, 2012* -
## Chemistry

The reaction for my lab is Mg(s)+2HCl(aq)--> MgCl2(aq)+H2(g) I need to find the pressure of the hydrogen gas. Initial Pressure = 0.98692 atm Total Pressure = 1.64816 atm I don't know if I calculated the pressure of hydrogen gas correctly. I used the

*asked on July 15, 2012* -
## Chemistry

How would I figure out what is produced during a chemical reaction between 0.5 grams of sodium bicarbonate and 3 grams of citric acid? I know that it produces carbon dioxide and water but my professor said I am missing something from my equation.

*asked on June 26, 2012* -
## chemistry

What products are formed when aqueous solutions of Na2SO4, Fe3SO42, and BaCl2 are mixed together ? Can someone help me write out a balanced equation for the reaction that occurs.

*asked on January 24, 2012* -
## Civics

I have a civics final tomorrw. the question I'm working on is "To Postpone Sentence/Fine" It is a crossword puzzle and the first letter is R - - - I - - - . the book says to suspend, but I can't fine any word that starts with R? Please help.

*asked on January 10, 2012* -
## Physics

A 34-g bullet traveling at 120m/s embeds itself in a wooden block on a smooth surface. The block then slides toward a spring and collides with it. The block compresses the spring (k=100 N/m) a maximum of 1.25 cm. Calculate the mass of the block of wood.

*asked on January 5, 2012* -
## Physics

A 10-g bullet is shot vertically into a stationary 8-kg block. The block lifts upward 3.0 mm. The bullet penetrates the block in a time of .001 seconds. Assume the force exerted on the block is constant. What is the impulse imparted on the block by the

*asked on November 30, 2011* -
## Math

What is 5x^2y^-3 over 25x^6y^2 in simplest form

*asked on November 13, 2011* -
## science

the lack of atmosphere.

*asked on November 8, 2011* -
## Chemistry

Calculate the mass of NaCl produced when 5.50 moles of Sodium reacts with excess chlorine gas.

*asked on May 21, 2011* -
## math- algebra- help please!

3 dice are rolled let (y,r,b) represent each outcome? a- sample space b- prob rolling a sum of 18 c- prob of rolling a sum less than 5

*asked on April 6, 2011* -
## Algbra

I need help with the following problem. -6 less than or equal to 3 + 1/3a less than or equal to 5 Please show steps and answer. Thanks.

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

A ball throw at 45 degree angle with an initial speed of 15m/s. the time for the ball to reach its highest point can be found from the data and known constants using which equation? solve for time?

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

How much iron can be recovered from 25.0 grams of FeO?

*asked on November 11, 2010* -
## math

20 divided 2 minus 24 divided by 3 equals ? No parenthesis

*asked on May 24, 2010* -
## Math

How many positive three-digit integers have the property that the tens digit is greater than or equal to the hundreds digit and the ones digit is greater than or equal to the tens digit? Please help :) thanks -Zach

*asked on April 21, 2010* -
## math

The value of a "Mint State-63" 1950 Jefferson nickel minted at Denver is 8/7 the value of a 1945 nickel at Philadelphia. Together, the total value of the two coins is $15. What is the value of each coin?

*asked on April 14, 2010* -
## College Chemistry

1) The concentration of the aluminum ion in a test solution is 0.10M. Using the Ksp for aluminum hydroxide (3. x 10^-34), calculate the concentration of hydroxide needed to precipitate aluminum hydroxide. From the concentration of the hydroxide, calculate

*asked on April 1, 2010* -
## Chemistry

If the yield from the reaction of acetic acid with isopentyl alcohol is 45% how many grams of isopentyl acetate are formed from 3.58g of acetic acid and 4.75g of isopentyl alcohol?

*asked on March 18, 2010* -
## Physics

A 120 g ball moving to the right at 4.2 m/s catches up and collides with a 450 g ball that is moving to the right at 1.2 m/s. If the collision is perfectly elastic, what are the speed and direction of each ball after the collision?

*asked on November 30, 2009* -
## Pre Calc

I am familiar with this type of problem but can't seem to get the right answer. Use the given zero to find the remaining zeros of each function f(x)=x^4-9x^3+7x^2-91x-348,zero 5-2i I normally would use synthetic division with the root 5-2i bringing it down

*asked on November 13, 2009* -
## math

Determine whether the functions are even, odd, or neither. (a) f(x) = x²/√x²+ 1 (b) g(x) = x^3 - √ x- 7

*asked on April 2, 2008* -
## Physics

Batman (mass = 90 kg) jumps straight down from a bridge into a boat (mass = 530 kg) in which a criminal is fleeing. The velocity of the boat is initially +20 m/s. What is the velocity of the boat after Batman lands in it?

*asked on February 25, 2008* -
## Physics

A 97.0-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.70 m/s2, (b) moving upward at a constant speed, and (c) accelerating downward with an acceleration of 1.80

*asked on February 18, 2008* -
## math

The scale model of a building is 5.4 feet tall. If the original building is 810 meters tall, what was the scale used to make the model?

*asked on November 19, 2019* -
## English

When Bruno presumes that ''heil Hitler'' is another way of wishing someone a pleasant afternoon, what literary element is suggested?

*asked on May 1, 2019* -
## Trig

How do you find the complementary and supplementary angles in degrees?

*asked on October 23, 2018* -
## Math

Amy went to the fall festival and bought at least 25 apples. The apples were a mix of gala apples and red delicious apples. Amy knows that she got more than twice as many gala apples as she did red delicious apples. This can be represented by the system

*asked on July 24, 2018* -
## Math

Write an inequality and solve. Two times the sum of a number and four is no more than three times the sum of the number and seven decreased by four.

*asked on July 19, 2018* -
## phyiscs

A 14.5 kg toy car is driving around a horizontal circular track with a period of 8.0 seconds. The radius of the circular track is 1.1 meters. What is the force of friction in Newtons between the car and the track that is necessary for the car to remain on

*asked on May 7, 2018* -
## physics

A 1500 kg car is rounding a curve with a radius of 204 meters on a level road. The maximum frictional force the road can exert on the tires of the car totals 4439 N. What is the highest speed at which the car can go to round the curve without sliding?

*asked on April 25, 2018* -
## physics

A 4231 kg car is rounding a curve with a radius of 42 meters on a level road. The car has a velocity of 23.9 m/s. Calculate the acceleration of the car in m/s2. did you guys get 13.6?

*asked on April 25, 2018* -
## physics

A 4231 kg car is rounding a curve with a radius of 42 meters on a level road. The car has a velocity of 23.9 m/s. Calculate the acceleration of the car in m/s2. did you guys get 13.6?

*asked on April 24, 2018* -
## physics

A 1500 kg car is rounding a curve with a radius of 204 meters on a level road. The maximum frictional force the road can exert on the tires of the car totals 4439 N. What is the highest speed at which the car can go to round the curve without sliding?

*asked on April 24, 2018* -
## Physics

A stationary 14 kg shell explodes into two pieces. If the 5 kg piece has a velocity of -70 m/s, determine the velocity of the other piece. Do not round your answer until the end! i got 38.89

*asked on April 9, 2018* -
## phyiscs

A train is moving at 17 m/s and has a mass of 2564 kg. A broken down car (loaded with heavy bricks) is stopped on the train track. Upon impact, the train and car get tangled together and travel at a constant velocity of 4 m/s. What is the mass of the

*asked on April 9, 2018* -
## physics

A 11722 kg freight train, coasting at 11 m/s, strikes a stationary 13855 kg box car. Determine the "CHANGE IN MOMENTUM" for the box car if the freight train and the box car couple together. Hint: Draw an "IF Chart" to solve. (This question has been updated

*asked on April 9, 2018* -
## physics

A 12784 kg freight train, coasting at 17 m/s, strikes a stationary 5450 kg box car. Determine the velocity of the train and the box car is they couple together.

*asked on April 9, 2018* -
## phyiscs

A train is moving at 13 m/s and has a mass of 2363 kg. A broken down car (loaded with heavy bricks) is stopped on the train track. Upon impact, the train and car get tangled together and travel at a constant velocity of 3 m/s. What is the mass of the

*asked on March 30, 2018* -
## Physics

A stationary 21 kg shell explodes into two pieces. If the 5 kg piece has a velocity of -53 m/s, determine the velocity of the other piece. answer this please

*asked on March 30, 2018* -
## physics

A bowling ball is rolling along a table with a constant velocity of 0.7 m/s. The table top is 1.1 meters (H) from the ground in height. Determine the horizontal range of the bowling ball as it falls to the floor. In other words, how far from the edge of

*asked on March 9, 2018* -
## Physics

2018-West High School-Trimester 3 Home Announcements Assignments Discussions Grades1 People Pages Files Syllabus Quizzes Modules Class Notebook Google Drive Office 365 Discovery Education Collaborations Flipgrid Physics Projectile Motion Quiz Started: Mar

*asked on March 9, 2018*