# charles

Popular questions and responses by charles-
## physics

consider a vertical piston system. the piston has a 50g mass and a given radius of 3mm. what amount of pressure does the piston exert? ( use g==9.8 m/s^2 )

*asked on June 2, 2015* -
## chemistry

Calculate the mass of oxygen (in mg) dissolved in a 5.00 L bucket of water exposed to a pressure of 1.13 atm of air. Assume the mole fraction of oxygen in air to be 0.21 and the Henry's law constant for oxygen in water at this temperature to be 1.3 x 10-3

*asked on May 26, 2014* -
## Physics

You are given vectors A = 5.0i - 6.5j and B = -2.5i + 7.0j. A third vector C lies in the xy-plane. Vector C is perpendicular to vector A and the scalar product of C with B is 15.0. Find the x and y components to vector C. Answer key shows x component is

*asked on August 30, 2014* -
## Physics

A baseball player leads off the game and hits a long home run. The ball leaves the bat at an angle of 30.0o from the horizontal with a velocity of 40.0 m/s. How far will it travel in the air? Working out please

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

How many times does a palindromic number appear on a 12 hour digital clock between 12 midnight and 12 noon?

*asked on October 18, 2016* -
## Math

Solve the equation sin2x=2cos2x, for 0 degrees

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

A piece of wood sinks in ethanol but floats in gasoline. Give a range of possible densities for the wood?

*asked on September 20, 2007* -
## Math

3. The population of Columbus, Ohio, in 2014 was about 823,000. The population of the United States was about 319 million in 2014. (a) Write each population in scientific notation. (b) About how many times larger was the population of the United States

*asked on September 20, 2016* -
## probability theory

3 students; A, B and C, are in a swimming race. A and B have the same probability of winning and each is twice as likely to win as C. Find the probability that B or C wins the swimming race. 3) Given three boxes as follows: Box A contains 3 red, 2 white

*asked on November 20, 2015* -
## math

For some constants $a$ and $b,$ let \[f(x) = \left\{ \begin{array}{cl} 9 - 2x & \text{if } x \le 3, \\ ax + b & \text{if } x > 3. \end{array} \right.\]The function $f$ has the property that $f(f(x)) = x$ for all $x.$ What is $a + b?$

*asked on August 12, 2019* -
## english

Choose the correct sentence pattern for the sentence below. I hereby declare Tuesday Shakespeare Day.

*asked on April 19, 2015* -
## math

The given box plots show the number of text messages Paul and Sally received each day on their cell phones. Select the true statement. A. The interquartile range of Paul's data is less than the interquartile range of Sally's data. B. The median of Paul's

*asked on May 21, 2019* -
## math

Dents and Dings Auto Body buys paint with a list price of $29,000. If the supplier extends trade discounts of 30/35/20, what is the trade discount amount?

*asked on August 24, 2013* -
## Physics

A person with a mass of 85kg. How much in newtons do they weigh on the earth and the moon?

*asked on February 11, 2008* -
## Chemistry

An increase in the average kinetic energy of a sample of copper atoms occurs with an increase in a- Concentration b- Pressure c- Volume d- Temperature

*asked on March 5, 2008* -
## decimals

Mark wants to paint a mural. He has 1 1/3 gallons of yellow paint, 1 1/4 green paint, and 7/8 gallon of blue paint. mark plans to use 3/4 gallon of each paint color. How many gallons of paint will he have left after painting the mural?

*asked on November 18, 2014* -
## Mathematics

An aeroplane leaves an airport A and flies on a bearing 035°for 1.5 hours at 600km/hr to airport B It then flies on a bearing 130° for 1.5hours at 400km per hour to an airport C calculate the distance from C to A and the bearing of C from A with the

*asked on December 30, 2019* -
## General Physics

A block sliding on a horizontal surface has an initial speed of 0.5 m/s. The block travels a distance of 1 m as it slows to a stop. What distance would the block have traveled if its initial speed had been 1 m/s? 1. 2 m 2. 1 m 3. more information is needed

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

Given that f(x) = x^k where k < 0, what is the range of f(x) on the interval [1,infinity)?

*asked on August 14, 2019* -
## chemistry

In the combustion of hydrogen gas, hydrogen reacts with oxygen from the air to form water vapor. If you burn 54.8 g of hydrogen and produce 4.90 × 102 g of water, how much oxygen reacted?

*asked on August 29, 2014* -
## chem

How would your experimental formula of magnesium chloride “MgClx” have been affected if your product was not dried completely before weighing it? Would “x” be too high or two low?

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

taryn and alastair both mow lawns. Each charges a flat fee to mow a lawn. The table shows the number of lawns in the past week, the time spent mowing lawns and the money earned. Taryn mowed 9 lawns. She spent 7.5 hrs mowing lawns. Taryn earned $112.50

*asked on December 3, 2014* -
## math

Thirty identical toothpicks were used to create the figure below. There are over 25 triangles in the figure. What is the fewest number of toothpicks that could be removed so that no triangles remain? The image is an equilateral triangle with base four.

*asked on August 14, 2019* -
## math

a student claims that if a fair coin is tossed and comes up heads 5 times in a row, then according to the law of averages the probability of tails on the next toss is greater than the probability of heads. What is your reply?

*asked on January 31, 2010* -
## math

two strips of fabric measure 14 2/3 inches and 20 7/8 inches in length. to form one length, the strips are sew together using 3/8 inch from each strip to make the seam. what is the final length of the fabric after the two strips are sewn together.

*asked on October 20, 2016* -
## chemistry

An increase in the average kinetic energy of a sample of copper atoms occurs with an increase in a. concentration b. pressure c. volume d. temperautre

*asked on March 5, 2008* -
## mathematics

solve :log (12x-10)=1+log2(4x+3)

*asked on January 11, 2020* -
## math

Melina walked her dog 2 1/5 miles. Cathy walked her dog 1 3/4 times as far as Melania did. How many more miles did Cathy walk her dog?

*asked on November 15, 2014* -
## Calculus-Derivatives

How is 6#sin(#x-1)/cos^3(#x-1) the derivative of f(x)= 3sec^2(#x-1)? #= Pi (I coulnd't find the symbol...sorry.)

*asked on September 28, 2008* -
## math

Suppose that $n$ is a positive integer such that in base $7$, then $n$ can be expressed as $\overline{ABC}_7$, and in base $11$, then $n$ can be expressed as $\overline{CBA}_{11}$. Find the largest possible value of $n$ in base $10$.

*asked on August 9, 2019* -
## math

A man walks due west for 4km. He then changes direction and walks on a bearing of 179 until he is south-west of his starting point.How far is he then from his starting point?

*asked on May 17, 2017* -
## algebra

{distinct letters in the word food}

*asked on April 11, 2014* -
## math

Let $A$ and $B$ be real numbers such that $\frac{A}{x-5}+B(x+1)=\frac{-3x^2+12x+22}{x-5}$. What is $A+B$?

*asked on August 13, 2019* -
## Physics

Find the sum of vectors A=5m

*asked on March 8, 2016* -
## algebra

5x/9-11=-51

*asked on September 20, 2012* -
## Science

Identify two segments parallel to HG

*asked on September 10, 2020* -
## math

Navin from Mauritius, Luka from Croatia, and Ian from Botswana are chatting in the lobby of a youth hostel discussing their part-time jobs. They learn that Navin makes 160 rupee per hour, Luka makes 25 kuna per hour, and Ian makes 34 pula per hour. If one

*asked on August 13, 2019* -
## chemistry

A 0.109g sample of a pure gaseous compound occupies 112ml at 100degrees and 750torr: what is the molecular weight of the compound. ANS=(30.2g,mol). Please I need the solution

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

A toy company manufactures miniature cars. They sell miniature sports cars in a box. They sell 12 miniature trucks in a box. Mrs. Murphy wants to buy an equal number of sports cars and trucks for the Boys and Girls Club. What is the least number of

*asked on August 16, 2015* -
## math

A woman wants to take her fox, chicken, and bag of corn across the river in her canoe. The canoe can hold only one thing in addition to the woman. If left alone, the fox would eat the chicken, or the chicken would eat the corn. How can the woman take

*asked on January 7, 2010* -
## Chemistry

A shiny gold colored car of metal weighting 57.3g has a volumes of 4.7cm^3. Is the bar of metal pure gold?

*asked on September 20, 2007* -
## Physics

It takes a runner 2 h, 43 min, 57 s to run a marathon. If the distance of a marathon is 42.2 km, what is the average speed of the runner?

*asked on September 23, 2020* -
## Chemistry

If 84.1 g of sodium hydroxide are reacted with 51.0 g of aluminum in the following equation: 2NaOH + 2Al + 2H2O --> 2NaAlO2 + 3H2 a) what mass of excess reactant remains? b) what mass of water would react?

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

In order to pass a physical education class at a university, a student must run 1.0 mi in 12.5 min. After running for 10.0 min (assume constant speed), she still has 510 yd to go. What constant acceleration does she need over the final 510 yd in order to

*asked on September 14, 2014* -
## Logic

Choose the pair of words/phrases among the choices that exhibits the same logical relationship as the words/phrases in the following pair. heavy : weight dry : wet feather : scale #hot : temperature color : size I placed a # next tom my answer.

*asked on September 11, 2011* -
## Chemistry

The density of water is 1.0 g/mL. How many deciliters of water will fill a 0.5-L bottle?

*asked on September 20, 2007* -
## physics

a sphere of radius r moving with velocity v through a fluid experiences a retarding force f given by F=6r^yv^zn^x where n is the viscosity of the liquid. use the method of dimensions to find the values of x,y,and z.

*asked on March 7, 2016* -
## math

4/5 * 3/4 = =16/20 * 15/20 =240/20 =12 is this right?

*asked on November 23, 2014* -
## Math

Elbert wants to plant grass seed in his backyard. His yard is shaped like a rectangle that is 6 meters by 7 meters. He plans to use a cup of seed for every square meter in his yard. How many cups of grass seed will he need?

*asked on February 28, 2013* -
## Math

Serena has a square-shaped garden. She wants to put a fence around the outside of the garden. One side of the garden is 8 feet long. How many feet of fence will she need?

*asked on February 28, 2013* -
## Math/Trig

Which logarithmic equation is equivalent to L^m = E 1) LogL E = m 2) logE L = m 3) logm E= L 4) logE m= L

*asked on February 11, 2012* -
## Trigonometry

This is a logs question If u=x/y^2, which expression is equivalent to log u? 1) log x + 2 log y 2) 2(log x- log y) 3) 2(log x + log y) 4) log x- 2 log y

*asked on February 11, 2012* -
## Electronics

With a carrier voltage of 80Vp-p and %m at 100 what is Vm,Vmax,Vmin,Vusb,Vlsb

*asked on May 5, 2008* -
## Mathematics

The 12th term of an AP is -41, given that first term is 3. Find the 20th term

*asked on July 7, 2020* -
## math

solve 7x = 42 show your work help plz

*asked on September 6, 2019* -
## math

There are numbers A and B for which A/(x-1)+ B/(x+1)=(x+2)/(x^2-1)for every number x≠±1. Find B.

*asked on August 14, 2019* -
## math

What is the minimum value of $y$ if $y=3x^2+6x+9?$

*asked on August 13, 2019* -
## Physics

A man walks 3km E and then 4km N. What is his resultant displacement?

*asked on March 8, 2016* -
## Physics

Find the magnitude of the dot product of the two vectors B=6i+j+2k, D=-1+3j. What is the angle between B and D

*asked on March 8, 2016* -
## math

A jar contains 133 pennies. A bigger jar contains 1 2/7 times as many pennies. What is the value of the pennies in the bigger jar

*asked on November 23, 2014* -
## General Physics

A force Fx acts on a particle. The force is related to the position of the particle by the formula Fx = (5.9 N/m3) x3. Find the work done by this force on the particle as the particle moves from x = 0.9 m to x = 22 m. Answer in units of J

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

A mother of triplets wants to buy gum balls the machine has two colors how much will it cost to get three gum apps the same color ?

*asked on February 14, 2013* -
## arithmetic

first term and larst term of a geometric progression is 42.if the forth term is greater than the second term by 168, find the first term.the forth term.

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

On a part-time job, you are asked to bring a cylindrical iron rod of length 91.9 cm and diameter 2.70 cm from a storage room to a machinist. Calculate the weight of the rod, w.

*asked on August 14, 2011* -
## stat

the time between unplanned shutdowns of a power plant has an exponential distribution with a mean of 20 days. Find the probability that the time between two unplanned shutdow is a) less than 14 days B) more than 21 days c) less than 7 days

*asked on January 11, 2011* -
## physics

a drop of oil of volume 000000000•1m spreads out on water to make a circular film of radius 0•1m what is the thickness of the film?

*asked on July 24, 2020* -
## History

I have an important essay about the three g's on god gold and glory. I need a hook, background, thesis statement. Thank You

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

Thirty identical toothpicks were used to create the figure below. There are over 25 triangles in the figure. What is the fewest number of toothpicks that could be removed so that no triangles remain? Triangle has base 4 and height 4

*asked on August 11, 2019* -
## Geometry

Two pyramids are similar. The surface area of the first is 250 and the surface area of the second is 22.5. The heights of the pyramids are in a ratio of _ : _ The volumes of the pyramids are in a ratio of _ : _ Two pyramids are similar.

*asked on July 19, 2019* -
## Math

A table tennis ball is dropped from a height of 5ft. The ball rebounds to 60% of its previous height after each bounce. Write an infinite geometric series to represent the distance that the ball travels after it initially hits the ground. (hint, the ball

*asked on June 11, 2019* -
## Algebra 2

Water towers are tall to provide enough water pressure to supply all of the houses and businesses in the area of the tower. Each foot of height provides 0.43 psi (pounds per square inch) of pressure. a. Write a sequence for the pressure in psi for each

*asked on June 10, 2019* -
## English 12

One goal of America Recycles Day is to raise awareness of the growing landfill problem. Which of these phrases is the complete infinitive phrase in the sentence?

*asked on November 6, 2018* -
## math

How many terms of the arithmetic sequence 88, 85, 82, . . . appear before the number -17 appears?

*asked on July 20, 2017* -
## math

The length by the width of Roxie's photo is 24 cm long and 14 cm wide. In order to make a photo that will fit into a wallet, the photo needs to be reduced to a length of 7 cm. Determine the width of the wallet size photo.

*asked on January 30, 2017* -
## Science

A 0.5kg mass connected to a light spring of constant 20N/M occilates on a frictionless track. Calculate the total energy of the system

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

I need help making this question into a equation? A cable television company charges $15 plus $5 each for extra services and now write an equation to show how much a person would pay for television if they had x number of extra services?

*asked on April 5, 2016* -
## Physics

If D=7i-3j+2k. Find the magnitude of D

*asked on March 8, 2016* -
## Physics

If D=7i-3j+2k and E=4i+5j-3k. Find the scalar product of D.E

*asked on March 8, 2016* -
## Physics

What is the total time of flight of an object projected vertically upwards with a speed of 30m/s? (g=10m/s^2

*asked on March 7, 2016* -
## physics

The vertical and horizontal component of the initial velocity of a projectile are 36m/s and 64m/s. Find the initial velocity and angle inclination

*asked on March 6, 2016* -
## maths

A rectangle of length y m and breadth 4 m less than the length. What is the perimeter??

*asked on March 4, 2016* -
## physcis

a girl throws a ball vertically upward with a speed of 20 ft/sec from the roof of a building 60 ft high.(a)how long will it take the ball to reach the ground? (b)what will its speed be when it strikes the ground?

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

Find the present value of the ordinary annuity. Please round the answer to the nearest cent.$2,000 per semiannual period for 7 yr at 12%/year compounded semiannually

*asked on December 30, 2014* -
## math

5/7 *9/10 =63/70 =9/10

*asked on November 23, 2014* -
## science

I am doing a titration lab and need help with a problem. (i used .100M H2SO4)(I used 10.0 ml of Ba(OH)2 solution and added 50.0 ml of distilled water making 60.0 ml total.) 1. Use the titration results to calculate the moles of H2SO4 that were used to

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

“Strontium-90 is a pure beta source.” How could a physicist test this statement? I am stuck on this one, but I was thinking through measurement of radioactivity.

*asked on August 30, 2013* -
## General Physics 1

A force ~F = Fx ˆý+Fy ˆ| acts on a particle that undergoes a displacement of ~s = sx ˆý + sy ˆ| where Fx = 10 N, Fy = −4 N, sx = 6 m, and sy = 1 m. 1. Find the work done by the force on the particle. Answer in units of J 2. Find the angle between

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

Laser Pointers emit light waves whose wavelength is 670 nm. What is the frequency for this light?

*asked on February 23, 2012* -
## PHYSICSI

The rotating loop in an AC generator is a square 11.0 cm on a side. It is rotated at 60.0 Hz in a uniform field of 0.800 T. Calculate the following quantities as functions of time t, where t is in seconds. (a) the flux through the loop mT·m2 (b) the emf

*asked on December 2, 2011* -
## physics

A small airplane with a wingspan of 13.5 m is flying due north at a speed of 70.8 m/s over a region where the vertical component of the Earth's magnetic field is 1.20 µT downward. (a) What potential difference is developed between the airplane's wingtips?

*asked on December 2, 2011* -
## math

Bairleys rectangular dog pen for his irish setter must have an area of 400 square feet. Also the length must be 50 feet longer than the width. Find the dimentions of the pen

*asked on November 21, 2011* -
## math

Having trouble solving: w^2 +5w -40

*asked on November 21, 2011* -
## advance algebra

how to find the lcm of 15,27

*asked on November 10, 2011* -
## MATH

HASAN MADE A MODEL FOR 437 HUNDREDS, 3 TENS,AND 7.WHAT ARE TWO OTHER WAYS HE COULD SHOW 437 USING BASE-TEN BLOCKS?

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

A pool of water with surface area of 0.6 hectares has a uniform depth of 3 metres.A pipe drains water in the pool at the rate of 200 litres per second.How much hours does it take to empty the pool?

*asked on August 19, 2011* -
## stat

given an exponential distribution with mean = 30 what is the probability that the arrival time is a) less than X = 0.1 B) greater than X = 0.1 c) between X=0.1 and X =0.2 d) less than X =0.01 or greater than X = 0.2

*asked on January 11, 2011* -
## Chemistry

A laser emitting light with a wavelength of 480 nm is directed toward the surface of rubidium metal. The work function for rubidium metal is 2.16 eV (1 eV = 1.602 x 10-19 J)

*asked on November 16, 2010* -
## Marketing

A) Explain why the return on investment diminishes as more is invested in advertising. I understand that ROI= (Gain from investment – Cost of Investment)/Cost of Investment. I guess I could say that the more you invest in advertising (Cost of Investment)

*asked on December 14, 2009* -
## Marketing

Explain why fixed and variable costs per unit decline as sales volume increases. Suppose a company had a variable cost/unit of $20 at a cumulative volume of 20,000 units. What would be their approximate variable cost per unit when they had produced 40,000

*asked on December 9, 2009* -
## Calculus

How is 2cos(4x) the derivative of f(x)=sin(2x)cos(2x)?

*asked on September 28, 2008*