Sunday

December 21, 2014

December 21, 2014

Total # Posts: 1,129

**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*

**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*

**Phyiscs**

A hollow copper tube (diameter = 4.01 cm) is sealed at one end and loaded with lead shot to give a total mass of 0.218 kg. When the tube is floated in pure water, what is the depth, z, of its bottom end?
*April 3, 2014*

**Physics**

A 4.8 kg container of water sits on a scale A. A cube of aluminum with sides of length 11.0 cm is suspended from a spring scale B so that half of the block is submerged in the water. What is the reading (in N) on spring scale B The continual question is What is the reading (...
*April 3, 2014*

**chemistry**

calculate the grams of solute neede to prepare 24 grams of a 13.5% by mass scurose (c12h22o11) solution
*March 27, 2014*

**math**

Let y=3(x-4)^2 -3 a) Show that y=3x^2 -24x +45 b) For the graph of y find both x intercepts by solving the equation 3x^2 -24x +45 =0 A) direction of opening B) x intercepts C) y intercept D) Axis of Symmetry E) Vertex F) max or min
*March 9, 2014*

**Math**

A person travels 8 mi, due north, 3 mi, due west and 7 mi due south how far are they from were they started?
*March 8, 2014*

**chem**

Hydrogen iodide can decompose into hydrogen and iodine gases. 2HI(g) mc026-1.jpg H2(g) + I2(g) K for the reaction is 0.016. If 0.148 atm of HI(g) is sealed in a flask, what is the pressure of each gas when equilibrium is established?
*March 5, 2014*

**math**

a piece of wire 24 ft. long is cut into two pieces. one piece is made into a circle and the other piece is made into a square. Let the piece of length x be formed into a circle. allow x to equal 0 or 24, so all the wire is used for the square or for the circle. How long should...
*March 4, 2014*

**Physic**

The figure below shows a block of mass m resting on a 20¡ã slope. The block has coefficients of friction ¦Ìs = 0.73 and ¦Ìk = 0.53 with the surface. It is connected via a massless string over a massless, frictionless pulley to a hanging...
*March 3, 2014*

**Literature**

thanks
*March 1, 2014*

**Literature**

Can someone help me with, the book "Invisible Man" and which character wore the mask.
*March 1, 2014*

**science**

Vanadium has several oxidation states. write correct formulas for vanadium oxide and vanadium oxide.
*February 25, 2014*

**science**

Vanadium has several oxidation states. write correct formulas for vanadium (iii) oxide and vanadium (v) oxide.
*February 25, 2014*

**Statistics**

Suppose x has a distribution with μ = 11 and σ = 5. (a) If a random sample of size n = 45 is drawn, find μx, σ x and P(11 ≤ x ≤ 13). (Round σx to two decimal places and the probability to four decimal places.)
*February 25, 2014*

**Chemistry 2**

A solution of NaOH (aq) contains 8.2 grams of NaOH(s) per 100.0 mL of solution. Calcualte Ph and POH at 25 degrees celsiuis
*February 21, 2014*

**Chemistry 2**

Calcualte PH and POh of an aqueous solution that is 0.050 M in HCL and 0.085 M in HBr at 25 degrees C
*February 21, 2014*

**Science**

Pu$$y !
*February 17, 2014*

**english literature**

can you help me comment on this theme please. awe and amazement
*February 8, 2014*

**Pre Algebra**

I have to create two dice (each on has six sides) they have to be numbered in such a way that the probability of rolling the numbers 1-12 are the same? I know this is a function but I am having trouble.
*February 7, 2014*

**physics (clear answer)**

An airplane traveling north at 400 m/s is accelerated due east at a rate of 50 m/s2 for 6 s. If the effects of air resistance and gravity are ignored, what is the final speed of the plane?
*February 5, 2014*

**physics (this one is killing me clear answer)**

At time t = 0 s, a puck is sliding on a horizontal table with a velocity 3.60 m/s, 35.0° above the +x axis. As the puck slides, a constant acceleration acts on it that has the following components: ax = –0.360 m/s2 and ay = –0.980 m/s2. What is the velocity of ...
*February 4, 2014*

**physics (clear answer)**

A golfer hits a shot to a green that is elevated 3 m above the point where the ball is struck. The ball leaves the club at a speed of 16.0 m/s at an angle of 38.5° above the horizontal. It rises to its maximum height and then falls down to the green. Ignoring air ...
*January 27, 2014*

**geometry**

A cylinder has a height of 16 cm and a radius of 5 cm. A cone has a height of 12 cm and a radius of 4 cm. If the cone is placed inside the cylinder as shown, what is the volume of the air space surrounding the cone inside the cylinder? (Use 3.14 as an approximation of π.)
*January 23, 2014*

**Algebra**

Thank you Ms. Sue, that helps a lot!
*January 20, 2014*

**Algebra**

A road map has a scale of 5/8 for every 125 miles. How many inches would be needed to represent 1000 miles on the map?
*January 20, 2014*

**Physics 221**

An electron is accelerated by a uniform electric field (1000 V/m) pointing vertically upward. Use energy methods to get the magnitude and direction of its velocity after it moves 0.10 cm form rest. Does the electron gain or lose potential energy?
*December 31, 2013*

**chemistry**

PV = nRT P = pressue V = volume n = moles R = 8.31 T = Temperature (0c = 273K) (103.0)(26.4) = n(8.31)(283) 2719.2 = n(2351.73) 2719.2 / 2351.73 = n m = 1.16
*December 4, 2013*

**Reading**

the wrong word is on. it is supposed to be in. you`re welcome.
*November 26, 2013*

**electromagnets**

A current loop with radius 20 cm and current 2 A is in a uniform magnetic field of 0.5 T. Considering all possible orientations of the loop relative to the field, what is the largest potential energy difference (in Joules) you can find between two orientations?
*November 22, 2013*

**electricity and magnetism**

A current of 20 mA flows in a single circular loop with a radius of 2 meters. A uniform magnetic field of 1.2 T points parallel to the plane of the loop. What is the magnitude of the magnetic moment of the loop in A-m^2? What is the magnitude of the torque on the loop in N-m?
*November 22, 2013*

Pages: **1** | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | Next>>