Wednesday

August 27, 2014

August 27, 2014

Total # Posts: 1,718

**Economics**

can someone teach me how to calculate per unit opportunity cost
*August 23, 2014*

**Economics**

Of your implicit and explicit costs of attending college, which is more, why?
*July 26, 2014*

**Calculus**

A water tank in the shape of a right circular cylinder has a volume that is increasing at the rate of 300pi cubic centimeters per hour. If the height is decreasing at the rate of 15 centimeters per hour, find the rate at which the radius is changing when the radius is 20 ...
*June 23, 2014*

**Calculus**

Water is leaking from the bottom of a tank in the shape of an inverted cone having an altitude of 12 feet and a radius of 2 feet. If the water is leaking at the rate of 0.25 cubic feet per minute, how fast is the water level decreasing when the water is 4 feet deep?
*June 23, 2014*

**physics**

Which one of these statements regarding standing waves on a string is FALSE Select one: a. The frequency of the first harmonic depends on the tension in the string b. The frequency of the first harmonic depends on the speed of the wave c. The frequency does not depend on the ...
*June 16, 2014*

**physics**

Which one of the following statements about standing waves on a string is FALSE? Select one: a. All other frequencies are integer multiples of the first harmonic b. The first harmonic is the lowest frequency standing wave that can be formed. c. The first harmonic has the ...
*June 16, 2014*

**physics**

The Bernouilli equation is a statement of which physical principle? Select one: a. COnservation of Momentum b. Newton's Second Law c. Pascal's Principle d. Conservation of Energy
*June 16, 2014*

**physics**

A mass of 2.9 g is hanging underneath a spring which has an unknown spring constant. The period of oscillation is 5.5 seconds. Find the spring constant in N/m. Give your answer to 2 s.f.
*June 16, 2014*

**physics**

A submarine dives down to a depth 9.5 beneath the surface of the ocean. Calculate the pressure in atmospheres at that depth, assuming the density of water is 1029 kg/m3, and the air pressure at the surface is 101.5 kPa
*June 15, 2014*

**physics**

A mass of 2.9 g is hanging underneath a spring which has an unknown spring constant. The period of oscillation is 5.5 seconds. Find the spring constant in N/m. Give your answer to 2 s.f.
*June 15, 2014*

**physics**

A spring and mass system are oscillating with an amplitude of 8.4 cm. The spring constant is 204 N/m and the mass is 540 g. Find the mechanical energy of the system to 2 sf.
*June 15, 2014*

**physics**

Which one of the following statements about an object performing Simple Harmonic Motion is TRUE? Select one: a. The object reaches its maximum speed as it passes through the equilibrium point. b. The object’s velocity is never zero. c. The object has a constant velocity. ...
*June 15, 2014*

**physics**

The elastic potential energy of an object may be negative Select one: True False
*June 9, 2014*

**physics**

You shoot a 57 gram dart vertically upwards from a catapult with a spring constant of 379 N/m. The catapult is initially stretched from the equilibrium point by 30 cm. What is the height above the starting point reached by the dart? Ignore air resistance and give your answer ...
*June 9, 2014*

**physics**

Which one of these statements concerning elastic collisions is FALSE? Select one: a. The two objects remain together after collision b. The kinetic energy is conserved c. The momentum is conserved
*June 7, 2014*

**physics**

You shoot a 57 gram dart vertically upwards from a catapult with a spring constant of 379 N/m. The catapult is initially stretched from the equilibrium point by 30 cm. What is the height above the starting point reached by the dart? Ignore air resistance and give your answer ...
*June 7, 2014*

**physics**

Which one of these statements regarding non-conservative forces is FALSE? Select one: a. A non-conservative force cannot have a potential energy defined for it. b. The work done by a non-conservative force may be either positive or negative depending on the direction of motion...
*June 7, 2014*

**physics**

Which one of these statements concerning elastic collisions is FALSE? Select one: a. The two objects remain together after collision b. The kinetic energy is conserved c. The momentum is conserved
*June 7, 2014*

**physics**

Which one of these statements regarding non-conservative forces is FALSE? Select one: a. A non-conservative force cannot have a potential energy defined for it. b. The work done by a non-conservative force may be either positive or negative depending on the direction of motion...
*June 7, 2014*

**Algebra**

Which represents the reference angle for 3pi/4? A) (3 pi)/4 B) pi/3 C) pi/4 D) pi/6 I have no clue on how to do this. (Looking at my unit circle I think A?)
*May 29, 2014*

**Algebra**

What is the period of the function? y = 2 cos pi x I said 2.
*May 29, 2014*

**Chemistry **

Which of the following explains why there are so many differences in the properties of peptides and proteins? A) several amino acid sequences are possible for proteins and peptides B) some proteins are enzymes while others are not C) proteins and peptides include nitrogen D) ...
*May 29, 2014*

**History**

How many administrations was Fidel Castro alive through? I know that he was alive through, Kennedy, and Reagan. Surely they are more can anyone help me?
*May 29, 2014*

**science**

A is correct. Good job.
*May 29, 2014*

**science**

I disagree, D actually sounds majorly preposterous. As well as C being outright impossible. Can you now decided between A or B?
*May 29, 2014*

**physics**

At a certain undisclosed place (probably not on Earth) an Atwood's like experiment gives the graph of 1/t2 vs Δm the slope is 3.8 (in 1/(kg s2). One also knows that h=1.3m, total mass =0.8kg and I/r2 = 0.08kg. what is the gravitational acceleration is (in m/s2)?
*May 28, 2014*

**physics**

For the system on the diagram, the string is massless, and slides over the pulley without friction. The masses are m1 = 5.7kg and m2 = 6.4kg. what is the magnitude of the acceleration of the system is ( in m/s2)
*May 28, 2014*

**physics**

A force 457 Newtons causes a displacement 6.2 metres which is at an angle of 8 degrees to the direction of the force vector. Calculate the work done by the force.
*May 26, 2014*

**physics**

A student of mass 64.7 kg climbs up the stairs in the Physics Department, with a vertical height change 3.1 metres. What is the change in gravitational potential energy? Give your answer in Joules, to 2 significant figures.
*May 26, 2014*

**physics**

What work is done by a friction force acting on an object? Select one: a. Always negative b. Always positive c. May be positive or negative depending on the choice of coordinate system d. Always zero
*May 26, 2014*

**physics**

You push your backpack, mass 2.8 kg across the desk with a force of 49.3 N. Calculate the acceleration of the backpack. Neglect friction forces and give your answer to 3 significant figures.
*May 26, 2014*

**Statistics**

1. This probability distribution shown below relates to the number of times a person goes to a local coffee shop per day. What is the expected mean (average) number of times a person goes to a local coffee shop per day? 2. What is the area equal to under a normal curve ...
*May 23, 2014*

**Chemistry**

What is [OH-] for a 4.72 X 10^-9M HCL solution? Would I just take 1.0X10-14 divided by 4.72X10-9?
*May 18, 2014*

**Math**

230
*May 13, 2014*

**Java**

What would happen if I did not give a access specifier. Would the class method or attribute be accessible to all other classes?
*May 7, 2014*

**Trigonometry**

Simplify each expression using fundamental identities. 1. Sin theta cot theta 2. 1-sin^2 theta / cos theta
*May 6, 2014*

**chemistry**

What volume of a 0.500 M solution should be diluted to make 250 mL of a 0.400 M solution?
*April 30, 2014*

**Math**

92-14=78
*April 30, 2014*

**physics**

(a) A hydrogen atom has its electron in the n = 5 level. The radius of the electron's orbit in the Bohr model is 1.323 nm. Find the de Broglie wavelength of the electron under these circumstances. (b) What is the momentum, mv, of the electron in its orbit?
*April 23, 2014*

**physics**

Gamma rays (γ-rays) are high-energy photons. In a certain nuclear reaction, a γ-ray of energy 0.306 MeV (million electronvolts) is produced. Compute the frequency of such a photon
*April 23, 2014*

**math**

which is larger .007 or .700
*April 23, 2014*

**chemistry**

What is the % yield of of a reaction in which 40.00g of tungsten(VI)oxide (WO3) reacts with excess hydrogen gas to produce metalic tungsten and 5.40mL of water. (assume the density of water is 1.00g/mL)
*April 22, 2014*

**chemistry**

in the reaction Al2O3= Al+O2 if 742.5 grams of Al2O3 are used how many mols of Al will be produced?
*April 17, 2014*

**Soc**

Is it important to distinguish between heterogeneity within a group and differences across several groups?
*April 10, 2014*

**Calculas**

The profit obtained when x barbecues are sold is P(x) = 100 x − 3x^2 (lnx) dollars . Find the marginal profit when 4 are sold.
*April 4, 2014*

**Chemistry**

a balloon has a volume of 2.0 L at room temperature (27 degrees celsius). at what temperature would the balloon have a volume of 2.0L?
*March 27, 2014*

**homonyms**

What is the homonym for do?
*March 24, 2014*

**Physics**

A 5.00-g bullet is fired into a 500-g block of wood suspended as a ballistic pendulum. the combined mass swings up to a height of 8.00 cm. What was the magnitude of the momentum of the combined mass immediately after the collision? Answer a. 0.394 kg·m/s b. 0.632 kg&...
*March 19, 2014*

**Phy**

A 5.00-g bullet is fired into a 500-g block of wood suspended as a ballistic pendulum. the combined mass swings up to a height of 8.00 cm. What was the magnitude of the momentum of the combined mass immediately after the collision? Answer a. 0.394 kg·m/s b. 0.632 kg&...
*March 19, 2014*

**Physics**

A 5.00-g bullet is fired into a 500-g block of wood suspended as a ballistic pendulum. the combined mass swings up to a height of 8.00 cm. What was the magnitude of the momentum of the combined mass immediately after the collision?
*March 19, 2014*

**Math**

Rey is playing a game. For every 2 steps forward he takes, he takes one step back. Complete the function table to show Rey's steps. Then write an equation for the function table. F 2-4-6-8-10 B _ _ _ _ _
*March 11, 2014*

**Math- NOT CALCULUS**

The hourly profit ($P) obtained from operating a fleet of n taxis is given by P=-2n^2+84n-45 What is the profit if 20 taxis are on the road? What is the maximum hourly profit? What number of taxis gives the max hourly profit? How much money is lost per hour if no taxis are on ...
*March 5, 2014*

**Math **

The hourly profit ($P) obtained from operating a fleet of n taxis is given by P=-2n^2+84n-45 What is the profit if 20 taxis are on the road? What is the maximum hourly profit? What number of taxis gives the max hourly profit? How much money is lost per hour if no taxis are on ...
*March 5, 2014*

**physics**

A block rests on a horizontal frictionless surface. A string is attached to the block, and is pulled with a force of 60.0 N at an angle θ above the horizontal. After the block is pulled through a distance of 2.00 m, its speed is 2.70 m/s, and 43.0 J of work has been done ...
*February 25, 2014*

**physics**

A 0.349 kg particle slides around a horizontal track. The track has a smooth, vertical outer wall forming a circle with a radius of 1.68 m. The particle is given an initial speed of 8.66 m/s. After one revolution, its speed has dropped to 6.05 m/s because of friction with the ...
*February 25, 2014*

**physics**

the rotation of earth is a period of 86164 seconds. the earth has a radius of 6380 km. how fast would you be moving due to earths rotation at the equator? also how fast would you be moving at a latitude of 27 degrees north of the equator? also calculate the centripetal ...
*February 24, 2014*

**physics**

if I weigh 177 lb on a stationary scale and stand on that same scale inside an elevator going up at an acceleration of 12 ft/s^2 the scale will read 238lbs. if the elevator, still moving upwards, decelerates at the rate of 32 ft/s^2 what will the scale read?
*February 24, 2014*

**physics**

if I weigh 177 lb on a stationary scale and stand on that same scale inside an elevator going up at an acceleration of 12 ft/s^2 what will the ending scale reading be?
*February 24, 2014*

**Math**

Kamal bought 7 packs of paper clips for a project. Then he bought 8 more packs. There are 25 paper clips in each pack. How many paper clips did he buy?
*February 21, 2014*

**Physics**

If the force between two charges decreases by a factor of 100 because the charges are moved further apart
*February 18, 2014*

**Physics**

What is the minimum uncertainty in the velocity of an electron that is known to be somewhere between 0.050 nm and 0.10 nm from a proton
*February 8, 2014*

**Physics**

A car is moving down a street at 67 km/h. A child suddenly runs into the street. If it takes the driver 1.26 s to react and apply the brakes, how many meters will the car have moved before it begins to slow down?
*February 6, 2014*

**Physics**

) What is the minimum uncertainty in the velocity of an electron that is known to be somewhere between 0.050 nm and 0.10 nm from a proton?
*February 5, 2014*

**math**

Shelby is organizing her 30 ribbons she won for competitions. She has twice as many first- place ribbons as she does second place ribbons. How many first-place ribbons does Shelby have?
*February 3, 2014*

**Physics**

A metal with a work function of 2.40 eV is illuminated by a beam of monochromatic light. If the stopping potential is 2.5V, what is the wavelength of the light?
*January 28, 2014*

**Macroecon**

What are the assumptions that could be made to simplify the study of the the after affects of Katrina on Louisiana's economy. 1. "Track the total net worth of the output produced by the state prior to the hurricane and after the hurricane." 2." Focus on ...
*January 18, 2014*

**Math Check 2 ?s quick**

The angle of elevation to the top of a 20-story skyscraper is measured to be 10 from a point on the ground 1,500 feet from the building. Find the height of the skyscraper in feet, correct to three decimal places. (Points : 5) 260.47 73.86 972.54 264.49 <-- Let f(x) = sin-...
*January 14, 2014*

**Chemistry**

-1368 kJ
*January 10, 2014*

**problem math**

laptop $1090.00 with 20% off and then another 15% taken off
*December 20, 2013*

**data management grade 12**

eight burglary suspects, two of whom are guilty, are placed in a line up. suppose that a witness is asked to identify the two guilty suspects but is unable to make a positive identification with any degree of confidence. if the witness feels compelled to identify two suspects...
*December 5, 2013*

**Math**

If the L.A. Dodgers win about 21 games a month, about how many games would they win after three months?
*December 4, 2013*

**econ**

a new sports store was selling 50 soccer balls for $20 each. recently the store changed the price to $30 each and sold only 30 soccer balls per day.what is the approximate price elasticity of demand for soccer balls?
*December 4, 2013*

**econ**

french horns and trumpets are substitutes in production. if the price of trumpets rises how will this affect equilibrium in the market for french horns?
*December 4, 2013*

**Math**

Find the area between x = 9.5 and x = 23 under a normal distribution curve with μ = 20 and σ = 4 .
*November 22, 2013*

**Math**

Find the area between x = 9.5 and x = 23 under a normal distribution curve with μ = 20 and σ = 4 .
*November 22, 2013*

**Physics**

A 0.60kg basketball is dunked vertically downward so that it leaves the [layer's hand at 8m/s. Assume it is released when the bottom of the ball is at the rim (3.05 meters off the ground). a). find acceleration of the ball once it leaves the player's hand b). how ling ...
*November 19, 2013*

**Physics**

A 0.60kg basketball is dunked vertically downward so that it leaves the [layer's hand at 8m/s. Assume it is released when the bottom of the ball is at the rim (3.05 meters off the ground). a). find acceleration of the ball once it leaves the player's hand b). how ling ...
*November 19, 2013*

**Physics**

I was confused there too cause the problem didn't tell me the displacement so I don't know how to find acceleration.
*November 19, 2013*

**Physics**

A juggler tosses a 0.4kg ball straight up at 8m/s, and then catches it at the same height . a. determine the acceleration on the way up and down b. determine the total amount of time spent in the air by the ball. (hint: you know the displacement) c.determine the velocity of ...
*November 19, 2013*

**Physics**

A juggler tosses a 0.4kg ball straight up at 8m/s, and then catches it at the same height . a. determine the acceleration on the way up and down b. determine the total amount of time spent in the air by the ball. (hint: you know the displacement) c.determine the velocity of ...
*November 19, 2013*

**Chemistry**

thats the part I cannot get.. how to balance them
*November 9, 2013*

**Chemistry**

Complete and balance the precipitation reactions. Include physical states in your equations. Ba(NO3)2(aq) + CuSO4 (aq)---> K3PO4(aq)+MgCl2 (aq)---->
*November 9, 2013*

**Algebra 1**

OH Thank you
*November 9, 2013*

**Algebra 1**

Which statement is always a correct conclusion about the values x and y in the function y=x-3? a. The value of x is always 3 less than the value of y b. The value of y is always less than the value of x c. When the value of x is positive, the value of y is also positive d. As ...
*November 9, 2013*

**Chemistry**

Among the following, which element has the lowest ionization energy? A. Na B. Cl C. Cs D. I
*November 8, 2013*

**physics**

bill and bob are both on the roof of a building 176.4 m high. bill drops a penny straight down at the same instant, bob throws a dime vertically upwards. the dime is thrown over the age when it comes back down it misses the roof and follows the penny to the street below. how ...
*October 27, 2013*

**physics**

bill and bob are both on the roof of a building 176.4 m high. bill drops a penny straight down at the same instant, bob throws a dime vertically upwards. the dime is thrown over the age when it comes back down it misses the roof and follows the penny to the street below. how ...
*October 27, 2013*

**Algebra 1**

I DID IT NEVER MIND
*October 22, 2013*

**math**

A log cabin in the shape of a rectangular prism is modeled using a scale of 1 cm : 0.6 m. If the dimensions of the model are 34 × 20 × 6 centimeters, what is the volume of the actual log cabin?
*October 15, 2013*

**Math Explanation**

Carl needs to estimate the quotient 547/92=. Explain how Carl could use compatible numbers to make a reasonable estimate.
*October 10, 2013*

**Chemistry**

A metal foil has a threshold frequency of 5.45× 1014 Hz. Which of the colors of visible light have enough energy to eject electrons from this metal.
*October 10, 2013*

**Chemistry**

The tripeptide is T-A-K 1. What is the overall charge of the tripeptide below pH 1.0? 2. What is the overall charge of the tripeptide at pH 12? 3. What type of intermolecular attractions could the side chains of the amino acids make with the solvent (water) at pH 7.4? (Note ...
*October 6, 2013*

**Chemistry **

1. What is the overall charge of the tripeptide below pH 1.0? 2. What is the overall charge of the tripeptide at pH 12? 3. What type of intermolecular attractions could the side chains of the amino acids make with the solvent (water) at pH 7.4? (Note that these are attractions...
*October 5, 2013*

**Science**

Briefly describe a desalination process. What can make desalination expensive? Name 2 renewable energy sources that can be used in desalination. Help me please and thankyou =)
*October 2, 2013*

**Math**

How would you solve this inequality -3(n+8)<-17-3n
*September 30, 2013*

**Math**

How you solve this in inequality form? Six less than or equal to the sum of 4 and -2x.
*September 25, 2013*

**Math**

How would you solve this word problem in one variable inequality form? The maximum safe water temperature in a spa is 104 degrees. The water temperature in bill's spa is 102 degrees. The temperature is increased by, d, degrees. Write and solve an inequality to show the ...
*September 25, 2013*

**Spanish 1**

No me gusta la lechuga porque no es _____. A. sabrosa B. sabroso C. malo D. horrible D?
*September 20, 2013*

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