# Zach

Most popular questions and responses by Zach-
## 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

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

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

*asked on July 6, 2012* -
## math

How does finding the square root of a number compare to finding the cube root of a number? Use the number 64 in your explanation.

*asked on October 31, 2012* -
## Social Studies

where is the moon when you are in a location experiencing a low tide

*asked on February 20, 2016* -
## Physics

I have one problem I just can't figure out, A machine in an ice factory is capable of exerting 3.30 * 10^2 N of force to pull large blocks of ice up a slope. The blocks each weight 1.21 * 10^4th N. Assuming there is no friction, what is the max angle that

*asked on October 13, 2010* -
## 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* -
## 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* -
## 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* -
## 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* -
## 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* -
## physics

Two air-track carts are sliding to the right at 1.0 m/s and held together by a string. The spring between them has a spring constant of 140 N/m and is compressed 4.5 cm. The carts slide past a flame that burns through the string holding them together.

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

A quantity of ice at 0.0 °C was added to 33.6 g of water at 45.0 °C to give water at 0.0 °C. How much ice was added? The heat of fusion of water is 6.01 kJ/mol, and the specific heat is 4.18 J/(g•°C).

*asked on January 26, 2015* -
## 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* -
## Social Stuides

What is one way that the United Nations shapes world affairs

*asked on September 28, 2015* -
## AP Chemistry

The reaction of 5.1 grams of fluorine with excess chlorine produced 4.5 grams of ClF3. What percent yield of ClF3 was obtained? Answer in unites of %

*asked on December 2, 2015* -
## 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* -
## 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

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

*asked on May 21, 2011* -
## chemistry

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

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

-6h + 4 - 3 + h = 11 4-3-11=6h-h -10=5h -2=h

*asked on September 21, 2006* -
## physics

A 57.5-kg runner has a speed of 5.80 m/s at one instant during a long-distance event. (a) What is the runner's kinetic energy at this instant? 967.15 J (b) If he doubles his speed to reach the finish line, by what factor does his kinetic energy change? im

*asked on October 5, 2015* -
## Physics

A cyclist approaches the bottom of a gradual hill at a speed of 20 m/s. The hill is 4.4 m high, and the cyclist estimates that she is going fast enough to coast up and over it without peddling. Ignoring air resistance and friction, find the speed at which

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

How Many Molecules are contained in 0.25 moles of Fe?

*asked on December 11, 2008* -
## physics

Two blocks are arranged at the ends of a massless string as shown in the figure. The system starts from rest. When the 4.01 kg mass has fallen through 0.412 m, its downward speed is 1.3 m/s. The acceleration of gravity is 9.8 m/s 2 .

*asked on December 9, 2015* -
## 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 60-cm-long, 500 g bar rotates in a horizontal plane on an axle that passes through the center of the bar. Compressed air is fed in through the axle, passes through a small hole down the length of the bar, and escapes as air jets from holes at the ends of

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

A cyclist approaches the bottom of a gradual hill at a speed of 20 m/s. The hill is 4.4 m high, and the cyclist estimates that she is going fast enough to coast up and over it without peddling. Ignoring air resistance and friction, find the speed at which

*asked on February 25, 2008* -
## 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

You are installing a new spark plug in your car, and the manual specifies that it be tightened to a torque that has a magnitude of 45 N·m. Using the data in the drawing, determine the magnitude F of the force that you must exert on the wrench. Lenght of

*asked on March 24, 2008* -
## 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

If 100.0 mL of 0.171 M Na2SO4 are added to 100.0 mL of 0.889 M Pb(NO3)2, how many grams of PbSO4 can be produced? Equation: Na2SO4 + Pb(NO3)2 = 2NaNO3 + PbSO4

*asked on September 22, 2016* -
## Algebra

The school that Trevon goes to is selling tickets to a choral performance. On the first day of ticket sales the school sold 12 adult tickets and 4 student tickets for a total of $188. The school took in $171 on the second day by selling 6 adult tickets and

*asked on December 3, 2009* -
## Chemistry

Draw the Lewis structure for each of these molecules. 1. PH3 2. H2S 3. HCl 4. CCl4 5. SiH4

*asked on January 28, 2015* -
## math

A roulette wheel has 18 red slots and 18 black slots numbered alternaetly with the numbers 1 through 36. Two green slots are numbered 0 and 00. The winning number is determined by the slot into which a single marble rolls. Players are not allowed to bet on

*asked on September 18, 2010* -
## 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* -
## 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* -
## 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* -
## AP Chemistry

If 400 mL of 3.5 molar HCl solution is added to 200 mL of 2.3 molar NaOH solution, what will be the molarity of NaCl in the resulting solution? Answer in units of M.

*asked on February 24, 2016* -
## math

With income earned by selling the rights to his life story, an actor invests some of the money at 3% and 30,000 more than twice as much at 4%. The total annual interest earned from the investments is $5600. How much is invested at each rate?

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

A museum curator moves artifacts into place on many different display surfaces. Use the values in Table 4-2 in the textbook to find Fs,max and Fk if you were to move a 157 kg aluminum sculpture across a horizontal steel platform. Fs,max: Fk:

*asked on November 18, 2010* -
## physics

Approximate the gravitational force of attraction between a 49.0 kg girl and a 52.0 kg boy if they are sitting 2.5 m apart

*asked on February 7, 2011* -
## Science

Predict what would happen to a reptile body temperature if the outdoor temperature increases by 10c.

*asked on March 16, 2009* -
## 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* -
## 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* -
## 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* -
## 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* -
## social studies

what are 2 unwritten practices of the roman republic?

*asked on January 9, 2013* -
## 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* -
## Physics

An automatic drier spins wet clothes at an angular speed of 4.8 rad/s. Starting from rest, the drier reaches its operating speed with an average angular acceleration of 3.6 rad/s2. How long does it take the drier to come up to speed?

*asked on March 6, 2008* -
## Social Studies (Check my answers please!)

What did the Mayan caldenders track? 1. Religous celebrations and battles 2. Religous celebrations and the seasons ** 3. Games of pok-ta-tok and the seasons 4. Games of pok-ta-tok and battles The Aztech capital of Tenochtitlan stood on the site of

*asked on March 27, 2017* -
## Algebra 1

Mary's class took two tests last week. 80% of the class passed the math test, 90% of the class passed the English test, and 72% of the class passed both. What is the probablility that a randomly selected student in Mary's class failed both tests? Express

*asked on November 5, 2009* -
## chemistry

When 1988 J of heat energy is added to 47.5 g of hexane, C6H14, the temperature increases by 18.5 °C. Calculate the molar heat capacity of C6H14.

*asked on April 7, 2013* -
## physics

An 8 g bullet is shot into a 4.0 kg block, at rest on a frictionless horizontal surface. The bullet remains lodged in the block. The block moves into a spring and compresses it by 7.9 cm. The force constant of the spring is 1400 N/m. What is the impulse of

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

A certain dog whistle operates at 23.5 kHz, while another (brand X) operates at an unknown frequency. If neither whistle can be heard by humans when played separately, but a shrill whine of frequency 9200 Hz occurs when they are played simultaneously,

*asked on April 23, 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* -
## 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* -
## Physical Science

What are the 4 nuclear forces? Out of the 4 which one is the strongest and which one is the weakest? Thanks http://hyperphysics.phy-astr.gsu.edu/hbase/forces/funfor.html THANK YOU As a side note, these are not nuclear forces. They are the four fundamental

*asked on April 11, 2007* -
## 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

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* -
## chemistry

How many grams of solid ammonium chloride should be added to 1.50 L of a 0.224 M ammonia solution to prepare a buffer with a pH of 8.720 ?

*asked on April 3, 2015* -
## 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* -
## 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* -
## 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* -
## 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

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* -
## math

from a square piece of cardboard with length and width of x inches, a square of width x-1 inches is removed from the center. Write the area of the remaining piece of cardboard as a function of x

*asked on February 13, 2013* -
## Chemistry

I am not sure if I calculated the exact molarity of the potassium permanganate. I multiplied the molarity of the potassium permanganate by the liters of potassium permanganate used in the titration and divided it by the total liters of solution. I don't

*asked on November 28, 2012* -
## Chemistry

ΔT = T(mix) - T(initial) And the equations is: HCl(aq)+ NaOH(aq) => NaCl(aq) + H2O(l) And T(mix) = 37 C 50.0 mL of 2.0M HCl = 23.7 C 50.0 mL of 2.0M NaOH = 23.5 C How do I find T(initial), do I just use their averages? Thanks

*asked on September 29, 2008* -
## 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* -
## physics

A knight sits on a castle wall during a siege.To while away the time, he notes that boulders catapulted from below land on the top of his wall with a vertical velocity of 9.9 m/s. If he is 35 m above the catapult, what is the initial velocity of the

*asked on September 25, 2015* -
## Algebra 2

find the real solutions of each equation by graphing. 2x^4=9x^2-4 15x^4=11x^3 + 14x^2

*asked on February 9, 2015* -
## Algebra 2

write the compound inequality 3.1 less then or equal to m less than or equal 4.7 as an absolute value inequality.

*asked on December 16, 2014* -
## Geometry

Help I need help to find the coordinates of the circumcenter of each triangle. Isosceles triangle CDE with vertices C(0, 6), D(0, –6), and E(12, 0)

*asked on November 15, 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* -
## Math

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

*asked on November 9, 2011* -
## Algebra 2

A Rectangular Field is to be enclosed by a fence and divided into three parts by another fencer. Find the maximum area that can be enclosed and separated in this way with 500 meters of fencing.

*asked on February 3, 2011* -
## Physics

A 5.50 kg cat leaps from the floor to the top of a 94.0-cm-high table. If the cat pushes against the floor for 0.220 s to accomplish this feat, what was her average power output during the pushoff period?

*asked on November 30, 2009* -
## Pre Calc (For Reiny)

Thanks so much your method worked perfectly! My solution was: the remaining zeros were 5+2i, 3, and -4 I have one question that's bugging me though, why is it that synthetic division did not work for me? I thought that long division and synthetic division

*asked on November 15, 2009* -
## Chemistry

Which stage of ionization usually produces more ions?

*asked on May 27, 2009* -
## 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 tennis ball may leave the racket on a serve by a top player with a speed of 45.0 m/s. If the ball's mass is 0.063 kg, and it is in contact with the racket for 0.030 s, what is the average force (in newtons) on the ball?

*asked on July 12, 2013* -
## 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* -
## chemistry

If 1/2 moles of 02 react with 24 moles of hydrogen, can 2 moles of water be produced?

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

A magician has 3 more red hats than black hats and 4 fewer purple hats than black hats and has 14 hatsin all. How many hats of each color does he have. Show how you got the answer.

*asked on September 14, 2009* -
## 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* -
## Algebra 2

what is the positive solution of the equation 5x^2 + 2x -16 =0? solve by factoring.

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

I am not sure if I calculated the exact molarity of the potassium permanganate. I multiplied the molarity of the potassium permanganate by the liters of potassium permanganate used in the titration and divided it by the total liters of solution. I don't

*asked on November 28, 2012* -
## Chemistry

How would I find the percent of water lost in alum after it has dried for a week? Wet Alum = 13.44g Dry Alum = 11.28g

*asked on September 11, 2012* -
## Chemistry

How would I calculate the heat of solution in Joules for dissolving 0.1 mole of NH4NO3 in 100 mL of water? The initial temperature was 22.8 degrees celsius and the temperature after the salt dissolved was 18.1 degrees celsius.

*asked on July 24, 2012* -
## physics

A block of mass M = 6.755 kg is pulled along a horizontal frictionless surface by a rope of mass m = 0.592 kg, as shown in Fig. 5-63. A horizontal force = 41.5 N is applied to one end of the rope. Assume that the rope only sags a negligible amount. Find

*asked on February 26, 2012* -
## Pre-Calc

Starkist tuna company will package tuna fish in 2-L cans. Find the radius and the height of the cans if the cans have a surface area which is less that 980 cm^2. I have no idea how to go about this, it seems like geometry to me. Can you give me some help?

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

a truck travels up a hill with a 12% incline. the truck has a constnt speed of 22m/s. what is the horizontal componet of the reucks velocity

*asked on October 31, 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* -
## English

What is the simple subject of ,Many stories about the first Valentine's Day exist?

*asked on September 5, 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*