# Zack

Most popular questions and responses by Zack-
## 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* -
## 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* -
## 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* -
## Science

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

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

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

*asked on March 20, 2013* -
## 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* -
## 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* -
## Physics to be solved

a horizontal scaffold, of length 2.00 m and uniform mass 50.0 kg, is suspended from a building by two cables. The scaffold has dozens of paint cans stacked on it at various points. The total mass of the paint cans is 79.5 kg. The tension in the cable at

*asked on January 14, 2013* -
## 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* -
## chemistry

formic acid is a weak acid with a ka value of 1.8x10^-4 at 25 celsius a solution with a concentration of .424M formic acid is prepared in a laboratory. 1) Write the ionization equation for an aqeous solution of formic acid 2)determine the ph of the

*asked on February 12, 2015* -
## math

which is greater, 100^10 or 10^100? explain reasoning.

*asked on October 18, 2012* -
## math

a group of 9 people spent $78 to go to the movies.adult tickets cost$10 each and student tickets cost $8 each.How many adult tickets were purchased?

*asked on January 31, 2012* -
## 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* -
## 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* -
## 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* -
## Chemistry 12

Determine the molar solubility of lead(II) iodide, PbI2, in 0.050 mol/L NaI. Ksp of PbI2 = 9.8 x 10^(-9)

*asked on April 23, 2013* -
## Physics

GPS can be used to determine positions with great accuracy. The system works by determining the distance between the observer and each of the several satellites orbiting Earth. If one of the satellites is at a distance of 20,000 km from you, what percent

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

A 1-m-tall barrel is closed on top except for a thin pipe extending 5.2m up from the top. When the barrel is filled with water up to the base of the pipe (1 m deep) the water pressure on the bottom of the barrel is 10 kPa. What is the pressure on the

*asked on February 26, 2015* -
## Physics

A uniform, solid, spherical asteroid with mass 1.2 * 10^13 kg and radius 1.0 km is rotating with a period of 4.6 hours. A meteoroid moving in the asteroid's equatorial plane crashes into the equator at 9.0 km/s. It hits at a 58° angle to the vertical and

*asked on November 9, 2012* -
## Math 117

1.) A rectangular solid and a circular cylinder have the same volume and the same height. The base of the rectangular solid is a square. Which (if any) of the following statements are true? (i) The rectangular solid and the cylinder have the same base

*asked on August 20, 2009* -
## 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* -
## physics

Hockey Puck A 110 g hockey puck sent sliding over ice is stopped in 13 m by the frictional force on it from the ice. (a) If its initial speed is 5.0 m/s, what is the magnitude of the frictional force? 1 N (b) What is the coefficient of friction between the

*asked on December 11, 2011* -
## 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* -
## 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* -
## Precal

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

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

The pK of acetic acid is 4.76. Which statement is true at pH 5.0? [A^-] = [HA] [A^-] < [HA] [A^-] > [HA]

*asked on August 28, 2011* -
## 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* -
## 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* -
## 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* -
## english

I need help with finding some poetry devices in the poem: Wordsmith by Susan young. I already have some, but would love a second opinion.

*asked on December 7, 2014* -
## 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* -
## geometry

We are learning about proofs. We drew lines between noncollinear points. Our table showed 2 points >> 1 line segment, 3 point >> 3 line segments, 4 points >> 6 line segments, 5 points >> 10 line seg, 6 points >> 15 line seg. etc. Write an expression in

*asked on October 8, 2008* -
## 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

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* -
## Physics

A projectile is shot straight up from the earth's surface at a speed of 1.20×104 km/hr. How high does it go?

*asked on April 6, 2010* -
## MATH

A FROG JUMPS A DISTANCE OF 25CM ON EACH JUMP.IF THE FROG JUMPS 6 TIMES ,HOW FAR DOES IT TRAVEL? EXPLAIN

*asked on November 23, 2011* -
## 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* -
## 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* -
## 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* -
## 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* -
## Advanced Functions

How do I verify this identity? (I've tried a lot but it's just not working) (sin2x + sin2y) = 2sin(x+y)cos(x-y)

*asked on January 17, 2013* -
## Physics

An engine block of mass M is on the flatbed of a pickup truck that is traveling in a straight line down a level road with an initial speed of 25 m/s. The coefficient of static friction between the block and the bed is μs = 0.566. Find the minimum distance

*asked on May 24, 2012* -
## 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* -
## 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* -
## HIstory

How did the Industrial Revolution impacted American Society economically, socially, politically, and morally.

*asked on May 4, 2010* -
## 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

Larry stands on a bathroom scale while riding up in an elevator. His mass is 75 kg. At the current time the scale reads 100 lb. assuming the upward direction is regarded as positive, what is Larry’s acceleration in m/s2? What is happening to the elevator

*asked on October 22, 2013* -
## 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* -
## ap stats-- probability

over a 5 year period of time, 80% of winter days in Philadelphia had an average temperature above freezing. 20% of those days had precipitation. Of the days with an average temperature below freezing, 15% had precipitation. A winter day is chosen at

*asked on October 24, 2012* -
## 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* -
## 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* -
## 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* -
## language arts(CHECK ANSWERS)

please check these answers there really quick. 11.the zoo has recently acquired pandas,giraffes and lions. were does a comma belong? A. After and B. After zoo C. After giraffes(I PICK THIS) D. After acquired 12.Hector would you please relax? where does a

*asked on February 18, 2014* -
## 11th grade physics

Rachel pulls her 177N suitcase at a constant speed by pulling on a handle that makes an angle (-) with the horizontal. Using frictional force on the suitcase as 27N and Rachels force on 43N on the handle to calculate the net force. 1. What angle does the

*asked on November 2, 2010* -
## physical science

What is the change in thermal energy of water in a pond with a mass of 1,000kg and a specific heat of 4,184j(kgdegreesc) if the water cools by 1 degree c

*asked on October 27, 2009* -
## life science

ok i really need help. like really bad. cant figure it out. ok here it is. a color blind man marries a woman with normal vision. of their three daughters, one is color blind. one of their two sons is also colorblind. what are the genotypes of the parents?

*asked on May 17, 2007* -
## Algebra

When setting the price of admission tickets for the amusement park, Tabitha wants the price for a two child, two- adult family to be $100. She also wants the adult tickets to cost $8 more than twice the cost of a child's ticket. How much should a child"s

*asked on September 12, 2013* -
## Chemistry

The complete combustion of 1.00 ml of octane increases the temperature by 22.7 degrees celsius. The density of octane is 0.7g/mL. What is the efficiency of the octane in heating the water?

*asked on February 4, 2013* -
## 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* -
## 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* -
## 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* -
## Math

Elizabeth took 13 minutes less than twice as long as Heather to solve the puzzle if their total time together was 23 minutes who took less time to solve the puzzle? How much less?

*asked on January 13, 2015* -
## 5th grade math

how many ways can you use a dime, quarter, and nickel to make .60 cents?

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

Draw the structural formulas of the expected products in the two following hydrolysis reactions. Breakdown of a Lipid reactions are glycerol and 3 fatty acids Draw the structural of the expected products in the two following hydrolysis reactions.

*asked on February 9, 2012* -
## 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* -
## 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* -
## Physics

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

*asked on August 18, 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* -
## Algebra

One side of a triangle is 3 inches shorter than twice the length of the shortest side. The third side is 5 inches longer than the shortest side. If the perimeter is 110 inches, find the lengths of all three sides. So what are all the three sides?

*asked on September 12, 2013* -
## physical science

Please help.How can the IMA of a screwdriver be increased?

*asked on October 20, 2009* -
## 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* -
## 4th grade Math

hello, I'm helping my son with his assignment but unsure if the answer is correct. Please help advise. Milton needs to find the product of two numbers. One of the numbers is 9. The answer also needs to be 9. How will he solve this problem? Explain. 3 x 3 =

*asked on November 3, 2011* -
## Math

What is 29x47 in expanded algorithm

*asked on January 24, 2016* -
## 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* -
## Math 115

The revenue from selling q items is R(q)=475q−q2, and the total cost is C(q)=175+6q. Write a function that gives the total profit earned, and find the quantity which maximizes the profit.

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

Ms Washington buy a refrigerator that is 6 feet high, 3feet deep and 4 feet wide ,how many floor space does she need to fit the refrigerator

*asked on March 12, 2013* -
## Physics

The driver of a car on a horizontal road makes an emergency stop by applying the brakes so that all four wheels lock and skid along the road. The coefficient of kinetic friction between tires and road is 0.39. The separation between the front and rear

*asked on January 14, 2013* -
## 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* -
## 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

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* -
## Math

If there are 12 square tiles and each tile measure 1 foot on each side ,how many non congruent rectangle can you make.Each rectangle must use all 12 tiles

*asked on March 12, 2013* -
## Math

What is the percent increase from 91,400,000 to 94,400,000?

*asked on October 18, 2012* -
## Operations Management

You are managing a breakfast and lunch only restaurant that sells all-inclusive plated meals (i.e. all lunches include any protein or hot foods as well as salads and sides on a single plate). You’ve decided to try and apply “drum-buffer-rope”. You

*asked on November 28, 2011* -
## trig

Suppose that the point P is the point on the unit circle that is associated by the wrapping function with the number 31. In which quadrant is the point P located?

*asked on September 27, 2011* -
## MATH

THERE ARE 7 GIRLS ON A BUS EACH GIRL HAS 7 BACKPACKS IN EACH BACKPACK, THERE ARE 7 BIG CATS FOR EVERY BIG CAT THERE ARE 7 LITTLE CATS ? HOW MANY LEGS ARE THERE IN THE BUS?

*asked on December 13, 2007* -
## 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* -
## social studies

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

*asked on June 17, 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* -
## Calculus

A ball is thrown vertically upward with an initial velocity of 135 feet per second, the ball’s height after t second is s(t) = 135t – 22t How to calculate average velocity from 1 to 3 seconds?

*asked on March 22, 2014* -
## Math

How many times larger is 2,300,000 sq. miles than 1,200,000 sq. miles?

*asked on October 18, 2012* -
## Gen. Chem 1

The density of 18% nh4cl is 1.05 grams/ml. What mass of nh4cl is in 425 ml of the solution?

*asked on March 19, 2012*