# Zack

Popular questions and responses by Zack-
## Chemistry

The equilibrium constant (Kp) for the interconversion of PCl5 and PCl3 is 0.0121: PCl5 (g) ↔ PCl3 (g) + Cl2 (g) A vessel is charged with PCl5, giving an initial pressure of 0.123 atm. At equilibrium, the partial pressure of PCl3 is __________ atm. I have

*asked on April 20, 2018* -
## Physics Problem

A runner hopes to complete the 10,000m run in less than 30 minutes. After exactly 27 minutes, there are still 1100m to go. The runner must then accelerate at 0.20 m/s^2 for how many seconds in order to achieve the desired time? I get 80.9 but I know that

*asked on August 30, 2009* -
## math

The 1st,5th,13th term of an arithmetic sequence are the first 3 terms of geometric sequence with a common ratio of 2. If the 21st term of the arithmetic sequence is 72, calculate the sum of the first 10 terms of the geometric sequence.

*asked on April 9, 2015* -
## space/astronomy

Rank the objects based on the strength of the gravitational force that would be felt by a spacecraft traveling at a distance of 10 AU from the center of each of the objects, from weakest to strongest. 1)red giant mass: 1Msun radius: 100Rsun 2)sun 3)white

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

The electric field lines surrounding three charges are shown in the figure below. The center charge is q2 = -15.9 µC.

*asked on April 2, 2013* -
## Science

Heat and pressure deep beneath the Earths surface can change any rock into A) chemical rock B) gemstone C) metamorphic rock D) sedimentary rock

*asked on February 15, 2017* -
## PreCalc

Find the slope of the radius of the unit circle that corresponds to the given angle. 7π/6 radians

*asked on September 8, 2015* -
## english

Create an accurate summary of “The Cold Equations” that details the important events of the story. Provide your answer in three to five sentences. Can someone help me with this please?

*asked on September 19, 2013* -
## Physics

An average family of four uses roughly 1200 liters (300 gallons) of water per day. (One liter = 1000 cm^3.) How much depth would a lake lose per year if it uniformly covered an area of 50 square kilometers and supplied a local town with a population of

*asked on August 10, 2009* -
## Precal

If sin (theta) = sqrt5 / 3 and cos (theta) = 2 / 3 which of the following is tan (theta)?

*asked on February 23, 2017* -
## math

Kayla needs to have $560.00 to buy a new laptop. She already has $200.00 in the bank. Each month she will add $45.00 to her bank account. How many more months until she has enough money to buy her laptop?

*asked on September 5, 2019* -
## math

2) Sven sells hamburgers at a ballpark. He earns $7.50/hour, plus $0.40 for each hamburger he sells. b) How many hamburgers must Sven sell to earn $100 in a 6.5 shift? How many hamburgers must Sven sell to earn $100 in a 6.5 shift?

*asked on October 17, 2012* -
## Math

The population, in millions, of a city t years after 2000 is given by the function P(t) = 2.9 - 0.008t. Which statement is true? A. The population is increasing by 8,000 people per year. B. The population is decreasing by 8,000 people per year. C. They

*asked on June 9, 2017* -
## geometry

Assume that lines that appear to be tangent are tangent. O is the center of the circle. Find the value of x. Figures are not drawn to scale. m

*asked on May 24, 2013* -
## 4th grade math help

Explain how the variable B has two different values in the two equations 6 - B = 5 b = 1 B + 5 = 15. B = 10 Thanks!

*asked on October 25, 2011* -
## Physics

How would one determine the percent uncertainty in theta and in sin of theta for the following: 1) theta = 15.0 degrees +/- 0.5 degrees 2) theta = 75.0 degrees +/- 0.5 degrees I'm not sure whether I divide or use some kind of formula.

*asked on August 11, 2009* -
## physics

A 270 caliber hunting rifle fires an 8.5 g bullet, which exits the gun barrel at a speed of 980 m/s. What impulse does the burning gunpowder impart to the bullet? If it takes 2 ms for the bullet to travel the length of the barrel, what is the average force

*asked on November 24, 2017* -
## math

The height of a baseball (h) in meters (t) seconds after it has been tossed out a window is given by the equation h= -5t^2 + 20t + 15. A boy shoots at the baseball with a trajectory of h= 3t +3. Will the paintball hit the baseball? If so at what height and

*asked on March 22, 2015* -
## Math

My divisor is 9, I am greater than 7 times 9, I am less than 8 times 9,my remainder is 7,what dividend am I ?

*asked on January 15, 2015* -
## Math

Hannah made 0.7 of her free throw in a basketball game,abra made 9/10 of her free throws,dena made 3/4 of her free throws,who was the best shooter and explain why you say so

*asked on June 1, 2014* -
## Math

Amita decides that she wants the molds to have a square base.How many of the possible molds can she use?

*asked on May 21, 2014* -
## Chemistry 12

Solid phosphorous is found in two forms: white phosphorous (P4) and red phosphorous (P). White phosphorous is the standard state. The enthalpy of the formation of red phosphorus is -17.6kJ. When 32.6 g of white phosphorous reacts to form red phosphorous.

*asked on January 18, 2013* -
## Algebra 2

Simplify sqrt80 -3 Sqrt63 - sqrt125 - sqrt175

*asked on January 18, 2013* -
## Ela Help!!!!!!!!!!!!!!!!!!!!!!!

what does Vegetarian - that's an old Indian word meaning lousy hunter mean?

*asked on December 1, 2011* -
## Physics

A disk with a rotational inertia of 7 kgm^2 rotates like a merry-go-round while undergoing a torque given by (5+2t)Nm. At time 1s, its angular momentum is 5kg m^2/s. what is its angular momentum at 3s? I can't figure out how to start this problem.

*asked on April 27, 2011* -
## Statistics

True or False, In simple linear regression analysis, if the error terms exhibit a positive or negative autocorrelation over time, then the assumption of constant variance is violated.

*asked on December 5, 2010* -
## 5th grade

the sum of eighty-nine and a number

*asked on March 2, 2010* -
## Precalculus

A pole sits on top of a tall building an observer on ground 17 m away from building finds the angle of elevation to the base of the pole to be 30 degrees and the angle of elevation to top of pole to be 45 degree. Find height of pole to nearest tenth. Draw

*asked on August 8, 2018* -
## math

if a man jobs 3 1/2 miles in 3/4 of an hour, how far can he jog in one hour?

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

To warm up for a match, a tennis player hits the 56.0 g ball vertically with her racket. If the ball is stationary just before it is hit and goes 5.40 m high, what impulse did she impart to it?

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

If f(x) = -3x + 8, find f(5)

*asked on June 9, 2017* -
## Math

An automobile dealership uses CODE = 1 for new automobiles, CODE = 2 for used automobiles, and CODE = 3 for separate accessories. A salesman’s commissions are as follows: on new automobile, 3% of the selling price but a maximum of $300; on used

*asked on May 23, 2017* -
## math

A bag is filled with green and blue marbles. There are 101 marbles in the bag. If there are 25 more green marbles than blue marbles, find the number of green marbles and the number of blue marbles in the bag.

*asked on February 24, 2017* -
## chemistry

Ba(OH)2(aq) + HCl(aq) BaCl2(aq) + H2O (g) Consider the unbalanced equation above. What is the concentration of the original hydrochloric acid solution if 18.0 mL of the acid reacts with 45.5 mL of 0.280 M barium hydroxide?

*asked on June 20, 2016* -
## Genetics, HELP!!!

Planet X, a recently discovered planet, contains life forms that have double-stranded DNA as the genetic material. The DNA on Planet X is transcribed into RNA which is translated into protein. Planet X DNA contains only two bases: guanine (G) and cytosine

*asked on February 21, 2016* -
## PreCalc

Find the equation of the line in the xy-plane that goes through the origin and makes an angle of 1.2 radians with the positive x-axis.

*asked on September 8, 2015* -
## Physics

what is the schwarzschild radius of a black hole with a mass of 1.68x10^43kg

*asked on August 18, 2015* -
## Math 115

A manufacture has been selling 1400 television sets a week at $480 each. A market survey indicates that for each $24 rebate offered to a buyer, the number of sets sold will increase by 240 per week. a) Find the price p(x) of each television as a function

*asked on March 26, 2015* -
## Math 115

The manager of a large apartment complex knows from experience that 90 units will be occupied if the rent is 444 dollars per month. A market survey suggests that, on the average, one additional unit will remain vacant for each 6 dollar increase in rent.

*asked on March 26, 2015* -
## Math 115

A fence is to be built to enclose a rectangular area of 320 square feet. The fence along three sides is to be made of material that costs 6 dollars per foot, and the material for the fourth side costs 14 dollars per foot. Find the dimensions of the

*asked on March 26, 2015* -
## Science

Why is photosynthesis an example of a chemical reaction, and why is it classified as endothermic?

*asked on March 13, 2015* -
## Physics

The road runner drops a boulder from a 53 meter high building. When the block is 14 meters above the ground, the 2 meter tall Wiley Coyote looks up and sees the boulder. How much time does he have to get out of the way?

*asked on November 3, 2013* -
## English

I think this is C if not Which analogy would best go with this one? branch:tree:: A. flower:garden B. teo:three C. tentacle:octopus D. near:far

*asked on October 13, 2013* -
## English

Would this be D if not Which analogy would best go with this one? A:Z:: A. girl:mother B. weight:pounds C. truth:lie D. prologue: epilogue

*asked on October 13, 2013* -
## Algebra

How many hands of 5 cards can be made from a standard deck of cards such that each hand contains exactly 1 red card and 4 black cards?

*asked on May 2, 2013* -
## Advanced Functions/Trig

Prove the following: sin(x+y)sin(x-y) = cos^2 (y) - cos^2 (x)

*asked on April 21, 2013* -
## Writing

Compare how beaver stole fire and stealing fire from Zeus are the same

*asked on March 20, 2013* -
## Chemistry

given: 25.9 kJ + 1/2 H2 + 1/2 I2 => HI how much energy is needed for the reaction of 4.57x10^24 molecules of iodine, I2, with excess hydrogen, H2?

*asked on December 18, 2012* -
## Math

use the unit circle to prove that tan(x/2) = (sin(x))/(1+cos(x))

*asked on December 12, 2012* -
## math

how do you write the number words for 0.03. Is it three hundredths.(2)and the number words for 0.76,is it seven tenths,six hundredths

*asked on November 14, 2012* -
## Ms. Sue help!!!

Is 87 rounded to 90 or 85? I have to round to nearest fifth

*asked on March 21, 2012* -
## Ela Help!!!!!!!!!!!!!!!!!!!!!!!

Which sentence is better? Warren had a newspaper business and was one of the United States Senate. Warren had a newspaper business and he was one of the United States Senate.

*asked on March 4, 2012* -
## Veterans Help!!!

what are the reasons to help a veteran?

*asked on November 13, 2011* -
## Science plz help

Igneous rock is produced by volcanoes. What do you know about the activity on Earth during the time the oldest layer of rock was produced?

*asked on October 27, 2011* -
## trig

Suppose that the point P(13,-30) is on the terminal side of the angle theta in standard position. What is sin(theta)? Give your answer to the nearest thousandth

*asked on September 27, 2011* -
## Algebra 2

I have to make a design on a graphing calculator using the first quadrant. I have to use linear, quadratics, circles, absolute value, and elipse. Please help.

*asked on May 11, 2011* -
## math

the area of a trapezoid is 45 square centimeters. the bases of the trapezoid are 10 centimeters and 8 centimeters what is the height of the trapezoid?

*asked on April 22, 2010* -
## Chemistry

All the following species are best described by writing at least two Lewis structures EXCEPT a. O3. b. SO2. c. d. e. SO3. Explanation thanks

*asked on April 13, 2010* -
## algebra 1

(1,3) and (-2,-4) is m= 1/2

*asked on April 11, 2010* -
## Algebra 1

3+6x

*asked on April 11, 2010* -
## Algebra 1

-5 [54-(99-18)] -5[54 +99 +19] -5 [ 153+19] -5[172] -860 f(x)=2x²-5x How can I simplify -860 to fraction? I know something like - 860/100

*asked on April 11, 2010* -
## Algebra 1

x+9y=8 (1) x=3-9y (2) x (3-9y)+9=8 3x -9y +9y=8 3x = 8 x= 2.6 Is this correct?

*asked on April 11, 2010* -
## Chemistry

What is the energy of an electron in the 2s orbital of a hydrogen atom?

*asked on February 9, 2009* -
## Science

I'm having trouble figuring out what the independent and dependent variables are in the following experiment: 1.

*asked on March 19, 2007* -
## Algebra

You invest $4000 in an account paying 4.1% continuously compounded interest. How much will you have in 8 years

*asked on May 29, 2020* -
## algebra

A subset of a given set may contain no elements, all the elements of the given set, or some of the elements of the given set. How many subsets can be found in {a,b,c,d,e,f,g}?

*asked on April 29, 2020* -
## Social Studies

The people have very few rights and are not free to own and operate businesses. Which statement is most likely true of the country in which these people live? (1 point)

*asked on March 26, 2020* -
## Online behavior

sorry my friend went to far but yeah we well never say bad language on this app again and we wont be rude and behave better and not come on this app again please forgive us never again but its okay

*asked on January 15, 2020* -
## finance

A 10-year bond with an annual coupon rate of 8%. The bond has face value of $1,000 and makes semiannual interest payments. If you require a 12% nominal yield to maturity on this investment, what is the maximum price you should be willing to pay for the

*asked on December 8, 2019* -
## math

im so confuzzled..... Salim and Medha are comparing results from a 2-day lab experiment. On Monday, Salim’s results showed that 0.907 of the particles were charged while Medha’s results showed that 88% of the particles were charged. On Tuesday,

*asked on September 12, 2019* -
## math

Exits on an interstate are numbered consecutively. The distance between Exit 12 and Exit 13 is 2.7 miles. The distance between Exit 13 and Exit 14 is 0.9 mile farther than the distance between Exit 12 and Exit 13. The distance between Exit 13 and Exit 15

*asked on November 1, 2018* -
## georgia history

what was the main reason for British and colonization of north America? A) to find gold B) to spread Catholicism C) to increase wealth through mercantilism D) to build a strong alliance with the spanish

*asked on September 27, 2018* -
## Rate of current and time

A ship travels downstream for 36 miles and then makes the same return trip upstream. The trip downstream took 3/4 of an hour less then the trip upstream. If the rate of the current is 4mph find the rate of the ship in still water and the time it takes to

*asked on August 8, 2018* -
## Math

A recatangular pen is to be made with 120 feet fencing. The pen is divided into 4 equal parts. And an existing property fence will be used for one long side. 1) If x represents the width of the fence express its area A(x) in terms of x 2) Determine the

*asked on August 8, 2018* -
## Funny question

I'm just curious to know are there any incentives or point system for answering questions here? Like what drives people to? Hobby, getting paid, bored or something else? Does this site have the same structure as ya4oo answers? If so, I kind of get it then.

*asked on August 8, 2018* -
## Distance across ocean

3 engineers decide to measure the distance across a small area of the ocean. Mojo and Norah are on opposite sides of the ocean. Ken is on land 4.1 miles away from mojo and 6.3 miles from Norah. If the angle formed at kens point is BCA is 37 degrees what is

*asked on August 8, 2018* -
## Maximum area.

A recatangular yard is to be made with 120 feet fencing. The yard is divided into 4 equal parts. And an existing property fence will be used for one long side. If x represents the width of the fence exeorsss its area A(x) in terms of x Determine the

*asked on August 8, 2018* -
## Precalc

A ship travels downstream for 36 miles and then makes the same return trip upstream. The trip downstream took 3/4 of an hour less then the trip upstream. If the rate of the current is 4mph find the rate of the ship in still water and the time it takes to

*asked on August 8, 2018* -
## Dimensions of wall

Width of a wall is 4 inches less then the length. The border that surrounds the wall is 2 inches wide and has an area of 240 square inches. What are dimensions

*asked on August 8, 2018* -
## physics

A 0.300 kg air-track glider moving at 2.20 m/s bumps into a 0.800 kg glider at rest. a.) Find the total kinetic energy after collision if the collision is elastic. b.) Find the total kinetic energy after collision if the collision is completely inelastic.

*asked on February 20, 2018* -
## Science

I have looked and I can not find the definition for acquired traits I'm looking for the def. part of speech & synonym Please help. Zack

*asked on January 3, 2018* -
## eastern michigan

A pole-vaulter just clears the bar at 4.24 m and falls back to the ground. The change in the vaulter's potential energy during the fall is -3500 J. What is his weight?

*asked on October 6, 2017* -
## Math

Jake is walking up hill in the sand. Every step Jake takes he climbs 2 feet up, but slides down 6 inches. How far has Jake traveled if he has taken 8 steps?

*asked on June 9, 2017* -
## Math

Given the function f(x) = 3x +4 Determine the value of f(x) for the point (-1, f(x))

*asked on June 9, 2017* -
## Sequences Math

Find the function rule. X = -2, -1, 0, 1, 2. Y = 9, 4, -1, -6 -11. Help please this is too hard

*asked on February 23, 2017* -
## English

what are two symptoms the author experiences when exposed to perfume?

*asked on September 22, 2016* -
## social studies

1. How important is cooperation to the success or failure of the canning cooperative?

*asked on June 17, 2016* -
## math

jessica depoists 3000 in the bank. her money doubles in 12 years. how much was her intrest rate per year(assume annual compounding)

*asked on June 2, 2016* -
## Algebra 1

A firework is launched from a cliff overlooking the ocean. The elevation of the firework shell, in feet above sea level, t seconds after launch is given by the expression -16t^2+157t+63. How high is the top of the cliff, in feet above sea level. We just

*asked on April 12, 2016* -
## Maths

A fair coin is tossed 5 times. If X is the discrete variable the # of tails obtained, a) Draw the probability distribution . b) Find P (X

*asked on March 22, 2016* -
## Genetics!!

What is the function of a eukaryotic promoter sequence?

*asked on February 21, 2016* -
## Math

For a specific type of machine part being produced, the diameter is normally distributed, with a mean of 15.000 cm and a standard deviation of 0.030 cm. Machine parts with a diameter more than 2 standard deviations away from the mean are rejected. If

*asked on February 12, 2016* -
## Geometry

X is a point 7cm from the center of circle O with radius 9 cm. AXB is a chord of the circle such that AX= 2 XB. Find the length of AB.

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

What is 29x47 in expanded algorithm

*asked on January 24, 2016* -
## physics

A 550.27 N force is moving a 396.46 kg block at a constant velocity across a wooden plank. What is the kinetic friction force?

*asked on January 15, 2016* -
## physics

A 19.62 kg block is sliding down a 34.52 degree incline at a constant velocity. What is the mu k of kinetic friction between the incline and the block?

*asked on January 15, 2016* -
## Physics

A solid ball is released from rest and slides down a ramp that makes an angle of 50 degrees with respect to the horizontal. a) What is the minimum coefficient of static friction between the ramp and the ball for no slipping to occur? b) Would this

*asked on November 17, 2015* -
## Math

A chemist wants to create a solution that is 24% acid. How many liters of a 40% acid solution must be added to 50 liters of an 18% acid solution to obtain this 24% acid mixture?

*asked on September 9, 2015* -
## Alaniz

An airplane is flying at an altitude of 4000 feet and descends at a rate of 200 ft./m determine whether the altitude is proportional to the number of minutes. Explain your reasoning?

*asked on September 1, 2015* -
## algebra 1

If you place one staple on an electrionc, the balance still reads 0.0 grams.However ,if you place 210 staples on the blance ,it reads 6.80 grams .What is the mass of one staple ? - i don't understand this can u explan it

*asked on August 22, 2015*