Friday

July 3, 2015

July 3, 2015

Total # Posts: 1,166

**Math**

How many four digit numbers use the digit 7 two or more times?
*June 14, 2015*

**chemistry**

A 2.500×10−2M solution of NaCl in water is at 20.0∘C. The sample was created by dissolving a sample of NaCl in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 999.3mL . The density of water at...
*May 24, 2015*

**chemistry**

A 2.500×10−2M solution of NaCl in water is at 20.0∘C. The sample was created by dissolving a sample of NaCl in water and then bringing the volume up to 1.000 L. It was determined that the volume of water needed to do this was 999.3mL . The density of water at...
*May 24, 2015*

**Calc**

A ball is thrown straight up from the top of a 200 foot building with an initial velocity of 40feet/second. acceleration due to gravity is -32feet/second. a) find a formula for the height of the ball at time t. b) how high does the ball rise before it begins to fall c) when ...
*May 5, 2015*

**Calculus**

Give a Right-hand sum approximation of integral 1 to 4 of x^2 with n=4? I have done this problem alot and my teacher says the answer is 30 but I cant get it. HELP
*April 19, 2015*

**Chem**

Potable water (drinking water) should not have manganese concentrations in excess of 0.05 mg/mL. If the manganese concentration is greater than 0.1 mg/mL, it imparts a foul taste to the water and discolors laundry and porcelain surfaces. In an acidic solution, manganese(II) ...
*April 18, 2015*

**Math**

Each day Julia's math Teacher gives class a warm up qs. It's true/false 20% of the times and multiple choice 80% . Julia gets 70% on true false correct and 90% on multiple choice correct. Julia answered today's question correctly. What's the probability that it...
*April 15, 2015*

**Math**

file:///C:/Users/Student/Downloads/plot2.png file:///C:/Users/Student/Downloads/ploy3.png file:///C:/Users/Student/Downloads/plot4.png
*April 3, 2015*

**Math**

file:///C:/Users/Student/Downloads/666994-3162012-122716-PM-1767412394.png
*April 3, 2015*

**Math**

the box and whisker plot show data for the test scores of four groups of students in the same class. which plot represents a group with a median grade below 65? (Posting plots in comments) I was thinking its A, but i'm not sure.
*April 3, 2015*

**math**

n/4=17/3
*March 26, 2015*

**chemistry**

Using each of the following equations, calculate the number total of moles of products that can be obtained through decomposition of 1.75 moles of the reactant? a. 2 NH4NO3---> 2 N2 + O2 + 4 H2O b. 2 NaClO3---> 2 NACl + 3 O2 answers are 6.12 and 4.38 but i don't ...
*March 25, 2015*

**science**

a person rolled a large ball across a field. What information is needed t determine how much work the person did?
*March 24, 2015*

**science**

Are there any websites that explain Mendelian genetics and show how to solve such problems in an easy, concise manner at an AP Bio level? Thank you
*March 18, 2015*

**Chemistry**

D. Ionic bonds; hold single atoms together
*March 18, 2015*

**Chemistry**

A 20.0-mL sample of 0.300 M HBr is titrated with 0.150 M NaOH. What is the pH of the solution after 40.3 mL of NaOH have been added to the acid?
*March 5, 2015*

**Algebra**

No wait, it's C right?
*February 18, 2015*

**Algebra**

A zero of a polynomial is: A. A real number that makes f(x) = 0 B. A real number that makes x = 0 C.A real or complex number that makes f(x) = 0 D. A real or complex number that makes x = 0 Is the answer A?
*February 18, 2015*

**Physics**

A car speeds up from 12 m/s to 20 m/s in 6.4s.If its mass is 1200 kg,what force must its engine provide ?
*February 11, 2015*

**HISTORY**

All of the following statements about the Declaration of Independence are TRUE except:
*February 11, 2015*

**Calculus**

Sketch the region enclosed by the curves x= 49-y^2 and x = y^2 - 49. Decide whether to integrate with respect to x or y. Then find the area of the region.
*February 9, 2015*

**Algebra**

Teri finds a pile of money with at least $600. If she puts $200 of the pile in her left pocket, gives away 4/5 of the rest of the pile, and then puts the rest in her right pocket, she'll have more money than if she instead gave away $600 of the original pile and kept the ...
*February 7, 2015*

**math**

C A D D C ^^ answers. 100%
*February 6, 2015*

**math**

what is the greatest common factor of the polynomial show? rectangle tiles that have 6x and 6 look like this: ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** !!! !!! !!! !!! !!! !!!
*January 31, 2015*

**math**

what is the greatest common factor of the polynomial show: rectangle tiles that have 6x and 6 look like this: ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** !!! !!! !!! !!! !!! !!!
*January 30, 2015*

**accounting**

the board of directors declares 15% stock dividend on10000 outstanding shares of$20 per common stock. Thee current market value is $25 per share. how should I journalize this entry?
*January 26, 2015*

**Math**

your mom sucks ass
*December 31, 2014*

**Physics**

You're right, it is small, but it's not a typo. How is the change in momentum 90*5?
*December 24, 2014*

**Physics **

Two students (90.0 kg and 60.0 kg) on roller skates face-to-face push against each other. The 90.0 kg student moves at 5.0 m/s just after their hands lose contact. I figured out part A (final velocity of 60.0 kg student) to be 7.5 m/s backward. I need help with part B. (b) ...
*December 24, 2014*

**Chemistry**

If a 40 gram sample of radioactive isotope was present at 4pm, but a 5 gram sample remained at 4:30 pm, what is the half-life in minutes?
*December 15, 2014*

**Probability**

placed marbles in a bag. 6 of the marbles are red and 4 of them are yellow. reach into the bag and remove two marbles. a.) i.) What is the probability that both of the marbes you draw out are red? ii.) What is the probability that both of the marbles that you draw out are the...
*December 8, 2014*

**Physiology**

ok great thank you
*December 1, 2014*

**Physiology**

Any more suggestions about a few more answers?
*December 1, 2014*

**Physiology**

Population Control Women's Rights Religious Reasons/Moral Reasons
*December 1, 2014*

**Physiology**

What would be (3) world arguments for birth control and two (2) world arguments against birth control?!
*December 1, 2014*

**science**

A jellyfish can propel itself with jets of water pushed out of its bell, a flexible structure on top of its body. The elastic bell and the water it contains function as a mass-spring system, greatly increasing efficiency. Normally, the jellyfish emits one jet right after the ...
*November 30, 2014*

**physics**

A jellyfish can propel itself with jets of water pushed out of its bell, a flexible structure on top of its body. The elastic bell and the water it contains function as a mass-spring system, greatly increasing efficiency. Normally, the jellyfish emits one jet right after the ...
*November 29, 2014*

**physics**

A hot air balloon is traveling vertically upward at a constant speed of 2.7 m/s. When it is 11 m above the ground, a package is released from the balloon. After it is released, for how long is the package in the air? The acceleration of gravity is 9.8 m/s 2 . Answer in units ...
*November 27, 2014*

**physics**

In Mostar, Bosnia, the ultimate test of a young man’s courage once was to jump off a 400-year-old bridge (now destroyed) into the River Neretva 24 m below the bridge. How long did the jump last? The acceleration of gravity is 9.8 m/s 2 . Answer in units of s
*November 27, 2014*

**trig**

solve each equation if 0 < x < 2pi. answer must be in radians 1. 4 cos x - 2 = 0 2. 3 sec^2 - 4 = 0
*November 24, 2014*

**Physics**

A piece of aluminum has a volume of 1.55 x 10-3 m3. The coefficient of volume expansion for aluminum is = 69 x 10-6(C°)-1. The temperature of this object is raised from 25.9 to 406 oC. How much work is done by the expanding aluminum if the air pressure is 1.01 x 105 Pa?
*November 23, 2014*

**physics**

You are trying to find out how high you have to pitch a water balloon in order for it to burst when it hits the ground. You discover that the balloon bursts when you have pitched it to a height of 17 m. With what velocity did the balloon hit the ground? The acceleration of ...
*November 19, 2014*

**physics**

The barrel of a rifle has a length of 0.976 m. A bullet leaves the muzzle of a rifle with a speed of 561 m/s. What is the acceleration of the bullet while in the barrel? A bullet in a rifle barrel does not have constant acceleration, but constant acceleration is to be assumed ...
*November 19, 2014*

**physics**

Two airplanes leave an airport at the same time. The velocity of the first airplane is 710 m/h at a heading of 27.5 ◦ . The velocity of the second is 650 m/h at a heading of 167◦ . How far apart are they after 3.3 h? Answer in units of m
*November 19, 2014*

**physics**

The initial speed of a body is 6.64 m/s. What is its speed after 1.38 s if it accelerates uniformly at 4.7 m/s 2 ? Answer in units of m/s
*November 19, 2014*

**Physics**

A primitive diving bell consists of a cylindrical tank with one end open and one end closed. The tank is lowered into a freshwater lake, open end downward. Water rises into the tank, compressing the trapped air, whose temperature remains constant during the descent. The tank ...
*November 11, 2014*

**Physics**

A wire is made by attaching two segments together, end to end. One segment is made of aluminum and the other is steel. The effective coefficient of linear expansion of the two-segment wire is 19.0 x 10-6 (C°)-1. What fraction of the length is aluminum?
*November 9, 2014*

**Physics**

A steel ruler is calibrated to read true at 21.6 °C. A draftsman uses the ruler at 44.5 °C to draw a line on a 44.5 °C copper plate. As indicated on the warm ruler, the length of the line is 0.314 m. To what temperature should the plate be cooled, such that the ...
*November 9, 2014*

**Physics**

1.71 kg of glass (ρ = 2.66 x 10^3 kg/m3) is shaped into a hollow spherical shell that just barely floats in water. What are the (a) outer and (b) inner radii of the shell? Do not assume the shell is thin. Volume = 2.66 * 10^3/1.71 V=1555.56 m^3 V=pi(r^2)h
*November 1, 2014*

**much needed help...**

Physics
*October 22, 2014*

**much needed help...**

The sugar concentration in a solution (e.g., in a urine specimen) can be measured conveniently by using the optical activity of sugar and other asymmetric molecules. In general, an optically active molecule, like sugar, will rotate the plane of polarization through an angle ...
*October 22, 2014*

**physics**

The sugar concentration in a solution (e.g., in a urine specimen) can be measured conveniently by using the optical activity of sugar and other asymmetric molecules. In general, an optically active molecule, like sugar, will rotate the plane of polarization through an angle ...
*October 21, 2014*

**physics**

The sugar concentration in a solution (e.g., in a urine specimen) can be measured conveniently by using the optical activity of sugar and other asymmetric molecules. In general, an optically active molecule, like sugar, will rotate the plane of polarization through an angle ...
*October 21, 2014*

**physics**

Ten meter long steel railroad rails are laid end to end, with no space between, on a hot day when the temperature is 115°F. Six months later the temperature has dropped to -2°F.How much space now exists between each rail?
*October 21, 2014*

**physics**

Ten meter long steel railroad rails are laid end to end, with no space between, on a hot day when the temperature is 115°F. Six months later the temperature has dropped to -2°F.How much space now exists between each rail?
*October 21, 2014*

**physics... PLEASE HELP**

An elephant can hear sound with a frequency of 15.0 Hz. What is the wavelength of this wave? The speed of sound in air is 343 m/s.
*October 21, 2014*

**physics... PLEASE HELP**

In a particle accelerator, a proton reaches an acceleration of 9.0 × 1013 m/s2. The mass of a proton is 1.7 × 10 -27 kg. What is the force on the proton
*October 15, 2014*

**physics**

A typical cell membrane is 8.0 nm thick and has an electrical resistivity of 1.3 × 107Ω.m. (i) If the potential difference between the inner and outer surfaces of a cell membrane is 75 mV, how much current ﬂows through a square area of membrane on a side? (ii...
*October 15, 2014*

**physics... PLEASE HELP**

I have this same question, hope you get the answer
*October 15, 2014*

**chemistry**

Suppose you add a small ice cube to room temperature water in a coffee cup calorimeter. What is the final temperature when all the ice is melted? Assume that you have 200.0 mL of water at 25.0 degrees Celsius and the ice cube weighs 15.0 g and is at 0.0 degrees Celsius before ...
*October 10, 2014*

**Algebra**

4 years ago my father's age was 4 times that of my age. At present the sum of my father's age and that of mine is 53 years . What is father's present age.
*October 5, 2014*

**Physics **

A washing machine drum has a diameter of 46 cm and spins at 400 revolutions per minute. Find the centripetal acceleration at the drum's surface. Give your answer in m/s
*September 29, 2014*

**Physics**

The mass of the Earth=Mg=5.97x10^24 kg. The radius of the Earth=RE= 6.38 x10^6 m. A) What is the weight of the 75 kg person? B) Determine the acceleration due to gravity aboard a space shuttle at an altitude of 400km.
*September 21, 2014*

**Stats**

Checking the weather. 60% chance of rain at the bears football game. In the past, when it rains, bears win ,44% of the time and when it doesn't rain they lose 27% of the time. What's the probability that at the next game, the bears win in the rain?? Thanks
*September 21, 2014*

**Math algebra**

A tailgator
*September 18, 2014*

**physic**

Predict the horizontal distance a cannon on a 15 m cliff will shoot if it's initial velocity is 140 m/s and it's inclined at 15 degrees.
*September 14, 2014*

**Science (college level)**

1. What solar temp is needed for the peak intensity of radiation to occue at .2 micrometers? Remembering that humans can see light only between .4 and .7 microns, would the sun look brighter or dimmer at this new temp? 2. How much variation in earth orbital distance from the ...
*September 12, 2014*

**Chemistry**

Ok, thank you! this makes a lot of sense. and the pKa is the -logKa? Ka=[NH4^+]=110?
*August 3, 2014*

**Chemistry**

pH=pKa+ log(conjugate base/conjugate acid) I have it in my notes, I just can't figure out the steps to solve this problem, or how it applies.
*August 3, 2014*

**Chemistry**

A solution made up of 1.00 M NH3 and 0.500 M (NH4)2SO4 has a pH of 9.26. a. Write the net ionic equation that represents the reaction of this solution with a strong acid. b. Write the net ionic equation that represents the reaction of this solution with a strong base. c. To ...
*August 3, 2014*

**Math**

there are 9 blue marbles, 4 black marbles, 5 white marbles and 6 red marbles. If the probability of drawing a blue marble is now 1/3, how many of the 6 marbles removed were blue?
*August 3, 2014*

**phi**

How would the Kantian moral theory apply in resolving the negative effects on a community? (Points : 1) By treating persons in the community as ends in themselves, then companies will strive to provide quality products as well as to remedy any negative effects imposed on the ...
*July 29, 2014*

**phi**

Which of the following does Peter Singer assert about the principle of equality? (Points : 1) People should have equal rights because they are factually equal. People with higher abilities, it stands to reason, should have greater rights. Different groups of humans should ...
*July 20, 2014*

**Math**

A bus tour company charges a flat fee for renting out the bus, and an additional amount for each person. If the price is quoted at $382 for 12 people and $430 for 16 people, what is the flat fee?
*July 4, 2014*

**math**

A formula has to be written that takes all the money into account and the time that the carpenter's will spend on the deck. We know that the store charges $1000 for materials and $30/hr on labor. So with that information we can say this: $1000 + ($30 * t) = total Where t ...
*June 15, 2014*

**Physics**

I think the answer might be 1361 N. The larger force will pull the rope in the direction of that force causing the tension to be 1361 N.
*June 14, 2014*

**Physics**

a) F = ma this is Newton's second law. For each team you are given F and m All you have to do is solve for a: a = F/m That should be easy to do. b) The tension is easy too, both teams are pulling on the horizontal so it's merely 1361 N - 1350 N = 11 N.
*June 14, 2014*

**financial**

The formula for compound interest (which this problem asks about) is: A = P(1+(r/n))^(nt) Where A is the amount you end with, P is the original/beginning amount, r is the interest rate, n is the number of times interest is compounded, and t is the number of years. So because n...
*June 14, 2014*

**Ethics**

The government doesn't have any imperative to enforce social and moral expectations on business, but it does anyways. Through various government agencies they direct the operations of businesses which is enforcement. This enforcement comes from regulations that were ...
*June 14, 2014*

**Statistics**

Suppose the mean income of 35-year-olds in the US is $25,000. A random sample of 150 35-year-olds in California results in a sample mean income of $26,600 and a sample standard deviation of $3800. At the 5% significance level, ca we conclude that the true mean income of 35-...
*May 23, 2014*

**chemistry**

which of these reactions if spontaneous? (a) Fe^0 + Mg +2 --> Mg^0 +Fe+2 (b) Fe+2 + Mg ^0 --> Fe^0 + Mg +2 write the half cell equations for the spontaneous reaction. which element is oxidized and which is reduced?
*May 16, 2014*

**Physics 270-1 Applied**

A rock is thrown down with an initial speed of 30.0ft/s from a bridge to the water below. It takes 3.50s for the rock to hit the water. (a) Find the speed (in ft. /s) of the rock as it hits the water. (b) How high is the bridge above the water?
*May 8, 2014*

**Game Development**

In relation to game AI what is a flocking behaviour? Give an example of flocking behaviour in a game.
*May 7, 2014*

**Trig**

Use the given information to evaluate sin (a+b). Exact answers only. No decimals. Tan a = 4/3, cos b ='-12/13; neither a nor b are in quadrant III.
*May 7, 2014*

**Physics**

A girl throws a ball at a fence 10m away. The ball is 2m from the ground when it leaves her hand with an initial velocity of v=8 i+8 j m/s. When the ball hits the fence its horizontal velocity component is reversed (the vertical velocity component is unchanged). Where does the...
*May 7, 2014*

**Statistics **

In a study of 200 students, 42 were found to have a GPA greater than 3.0. Find a 98% confidence interval estimate of the proportion, p, of all students that have a GPA greater than 3.0.
*May 4, 2014*

**Physics**

is there any way i can get ur email so i can send the pic of the question
*May 1, 2014*

**Physics**

A block of mass M1positioned on a slope (at an angle ) is connected by means of an inextensible wire, of negligible mass, to another mass, m2, suspended from a frictionless pulley. The coefficients of static and dynamic friction between the slope and M1are 0.3 and 0.2...
*May 1, 2014*

**math**

marissa pours 1 1/2 cups of punch in each glass how many fluid ounces is each serving?
*April 22, 2014*

**chemistry**

.93 volts, .41 volts, and 1.99 volts. I tried to find them out with "doctor" bobs way but I couldn't do them. My teacher did not even bother to teach us how to do this. For future reference Dr. Bob, instead of asking for one's work, how about at least show ...
*April 11, 2014*

**Physics**

45.3?
*April 11, 2014*

**Physics**

A force platform is a tool used to analyze the performance of athletes measuring the vertical force that the athlete exerts on the ground as a function of time. Starting from rest, a 60.0 kg athlete jumps down onto the platform from a height of 0.600 m. While she is in contact...
*April 8, 2014*

**Physics **

An astronaut of mass 84.0 kg is taking a space walk to work on the International Space Station. Because of a malfunction with the booster rockets on his spacesuit, he finds himself drifting away from the station with a constant speed of 0.570 m/s. With the booster rockets no ...
*April 8, 2014*

**Physics**

Most of us know intuitively that in a head-on collision between a large dump truck and a subcompact car, you are better off being in the truck than in the car. Why is this? Many people imagine that the collision force exerted on the car is much greater than that experienced by...
*April 8, 2014*

**physics (clear answer)**

Multiple-Concept Example 10 provides one model for solving this type of problem. Two wheels have the same mass and radius of 5.0 kg and 0.47 m, respectively. One has (a) the shape of a hoop and the other (b) the shape of a solid disk. The wheels start from rest and have a ...
*April 3, 2014*

**physics (clear answer)**

The wheels, axle, and handles of a wheelbarrow weigh W = 56.2 N. The load chamber and its contents weigh WL = 584 N. The drawing shows these two forces in two different wheelbarrow designs. To support the wheelbarrow in equilibrium, the man's hands apply a force to the ...
*April 3, 2014*

**physics (clear answer)**

Two children hang by their hands from the same tree branch. The branch is straight, and grows out from the tree trunk at an angle of 26.1° above the horizontal. One child, with a mass of 43.6 kg, is hanging 1.31 m along the branch from the tree trunk. The other child, with...
*April 3, 2014*

**Physics**

A particular garden hose has an inside diameter of 15/16 in. The nozzle opening has a diameter of 5/16 in. When the flow speed of the water in the hose is 0.58 m/s, what is the flow speed through the nozzle?
*April 3, 2014*

**Physics**

A spherical hydrogen-filled balloon is used to lift a load of 5950 N (in addition to the weight of the hydrogen). Suppose the density of the air is 1.18 kg/m3. Find the minimum necessary radius for the balloon
*April 3, 2014*