Thursday

March 26, 2015

March 26, 2015

Total # Posts: 40

**Maths**

Your grandmother opened an investment account of $1,000(initial deposit) 15 years ago. Today it's worth $39,533.32 What is average annual rate of return that she earned? Thank you.
*February 12, 2014*

**math**

Subjects were asked to taste two wine samples in sequence. Both samples given were the same wine although subjects were expecting to taste two different samples. Of the 32 subjects in the study, 22 selected the wine presented first when presented with two identical samples. A...
*April 2, 2013*

**chemistry-redox **

Can two elements both be oxidized in a reaction? 2FeS + 4.5O2 +2H2O==> Fe2O3 + 2H2SO4 I see Fe is oxidized, going from Fe+2 to Fe+3 However, Isn't S going from S-2 to S+6? making sulfur ixidized too, and not reduced?
*January 21, 2013*

**Chemistry**

Dr. Bob222, Please see my additional posts on Jan 20 at 2:26pm and Jan 21 at 12:33 am. This is in reference to the redox reactions: 1) Fe goes from +2 to +3, and S goes from -2 to +6. They both appear to be oxidized because they increased. Is it possible that both can oxidize...
*January 21, 2013*

**chemistry - Please help**

Dr. Bob222, Ok, I'm starting to see how to get the oxidation numbers. However, since S goes from -2 to+6, does it also oxidize? is it possible that both can oxidize? I thought one oxidized while the other reduced.
*January 19, 2013*

**chemistry - Please help**

DrBob222, I understand that oxidation is a loss, but appears as an increase. I still have two questions. 1) Fe goes from +2 to +3, and S goes from -2 to +6. They both appear to be oxidized because they increased. Please explain. 2)I think my problem is that I don't ...
*January 19, 2013*

**chemistry - Please help**

In the redox reaction: 2FeS + 4.5 O(subscript 2)+ 2H(subscript 2)O > Fe(subscript 2)O(subscript 3) + 2H(subscript 2)SO(subscript 4) Fe is oxidized or reduced (select one) from ___ to ___. S is oxidized or reduced (select one) from ___ to ___.
*January 19, 2013*

**math - please help**

The 7 inch diameter drive drum of a belt conveyor is turning at 130 rpm. What is the belt speed (ft/min) if there is no slip between the belt and drum?
*March 30, 2012*

**math **

The 7 inch diameter drive drum of a belt conveyor is turning at 130 rpm. What is the belt speed (ft/min) if there is no slip between the belt and drum? What are the steps to figures this out? Thank you for your help.
*March 29, 2012*

**math**

What is the tip speed (ft/min) of a 21 inch long rotary lawn mower blade that is connected to the output shaft of an engine operating at 3400 rpm? What are the steps to figure this out?
*March 28, 2012*

**physics**

under the influence of its drive force, snowmobile is moving at constant velocity along a horizontal patch of snow. When drive force is shut off, snowmobile coasts to a halt. a) During the coasting phase, what is the net external force acting on the snowmobile b) How does work...
*February 12, 2012*

**Physics**

A diagram has vector A at 30 degrees above the positive x axis. length = 3 m Vector B is ON the negative x-axis. length = 1 m Vector C is ON the negative y-axis. Length is 2 m What is the direction in degrees of vector a + vector B + vector C?
*January 29, 2012*

**Physics please help**

A duck has a mass of 2.8 kg. As the duck paddles, a force of 0.05 N acts on it in a direction due east. In addition, the current of the water exerts a force of 0.15 N in a direction of 60° south of east. When these forces begin to act, the velocity of the duck is 0.12 m/s ...
*January 21, 2012*

**algebra**

a man 6.2 feet tall stands 12 feet away from a streetlight and casts a 5 ft shadow. How tall is the streetlight?
*December 3, 2011*

**Econ - please help**

demand for sulfur dioxide by coal-fired electricity electricity producers is: P= 1,000 - 16Q where Q is quantity of sulfur dioxide measured in thousands of tons, and P is price per ton of sulfur dioxide. Supposed EPA restricted the number of one-ton sulfur dioxide permits to ...
*November 15, 2011*

**ECON - urgent please help**

demand for sulfur dioxide by coal-fired electricity electricity producers is: Firm A's demand: P= 1,000 - 80 Q Firm b's demand: P= 1,000 - 20 Q where Q is quantity of sulfur dioxide measured in thousands of tons, and P is price per ton of sulfur dioxide. a)With the ...
*November 15, 2011*

**Econ - more help please**

demand for sulfur dioxide by coal-fired electricity electricity producers is: Firm A's demand: P= 1,000 - 80 Q Firm b's demand: P= 1,000 - 20 Q where Q is quantity of sulfur dioxide measured in thousands of tons, and P is price per ton of sulfur dioxide. a)With the ...
*November 14, 2011*

**Econ - help please**

demand for sulfur dioxide by coal-fired electricity electricity producers is: P= 1,000 - 16Q where Q is quantity of sulfur dioxide measured in thousands of tons, and P is price per ton of sulfur dioxide. a)With no policies or restrictions on sulfur emisssions, how much sulfur ...
*November 14, 2011*

**ECON**

demand for sulfur dioxide by coal-fired electricity electricity producers is: P= 1,000 - 16Q where Q is quantity of sulfur dioxide measured in thousands of tons, and P is price per ton of sulfur dioxide. a)With no policies or restrictions on sulfur emisssions, how much sulfur ...
*November 14, 2011*

**math **

5^(-x+3) = 64 I have only had exponents to the x, not with +3 too.
*November 5, 2011*

**algebra - more help please**

A thermometer reading 7 degrees C is brought into a room with a constant temperature of 29 degrees C. If the thermometer reads 15 degrees C after 4 minutes, what will it read in 6 minutes? 11 minutes? So I guess I need to put into newton's law of cooling: u(t) = T + (u sub...
*October 29, 2011*

**algebra - more help please**

Still lost. I put in 6 and lost a variable. T(6) = 29 - (29 - 7) e^-0.678 29 - 22e^-0.678 -29 = -22e^-0.678 ln 1.318181818 = e^-0.678 0.276253377 = -0.678
*October 29, 2011*

**algebra - help please**

A thermometer reading 7 degrees C is brought into a room with a constant temperature of 29 degrees C. If the thermometer reads 15 degrees C after 4 minutes, what will it read in 6 minutes? 11 minutes? So I guess I need to put into newton's law of cooling: u(t) = T + (u sub...
*October 29, 2011*

**Math - more help please**

A thermometer reading 7 degrees C is brought into a room with a constant temperature of 29 degrees C. If the thermometer reads 15 degrees C after 4 minutes, what will it read in 6 minutes? 11 minutes? So I guess I need to put into newton's law of cooling: u(t) = T + (u sub...
*October 29, 2011*

**math**

A thermometer reading 7 degrees C is brought into a room with a constant temperature of 29 degrees C. If the thermometer reads 15 degrees C after 4 minutes, what will it read in 6 minutes? 11 minutes?
*October 29, 2011*

**algebra**

Find all solutions to x^4 + 3x^2 = 4x^3 + 1
*October 16, 2011*

**algebra**

OK, I got it.
*October 15, 2011*

**algebra**

solve system of equations: y = 2x^3 - 2x^2 y = -6x^2 +30x I know (0,0) is one point. How do I get others?
*October 15, 2011*

**algebra**

so how do i find the max volume?
*October 15, 2011*

**algebra**

open box made from 33 x 33 inch sheet of metal by cutting out x-inch square from each corner and folding up the sides. What size square should be cut out to produce a box of maximum volume? (This is algebra class)
*October 15, 2011*

**algebra**

cannon fired ffrom top of 50 ft hill. height of shell above water: h = -0.0000167x^2 + 0.23x + 50 where x is horizontal distance from the foot of the hill to a point directly under the shell. How high does the shell go, and how far away does it hit the water? Hint: how high ...
*October 10, 2011*

**math**

Assume r and s are the roots of the quadratic equation ax^2 + bx + c = 0, show that r + s = -b/a and rs = c/a.
*October 10, 2011*

**physics**

if three resistances in parallel circuit are all equal, the total resistance is ___ the resistance of any on branch.
*May 18, 2011*

**physics**

if three resistances in parallel circuit are all equal, the total resistance is ___ the resistance of any on branch.
*May 18, 2011*

**physics**

Three identical resistors are connected in series to a battery. The voltage drop across one of the resistors is ___ times the voltage of the source.
*May 18, 2011*

**physics**

Electric power is found by multiplying ___ by current. volts? potential difference? The kilowatt hour is a unit for measuring ___. energy or electrical energy Thanks
*May 2, 2011*

**physics - please hellp**

I need help with two questions: 1) An object can only have a charge that is an integral multiple of the charge on the ___. Am I correct with "electron" as the answer? or possibly elementary charge? 2) The difference in potential between any two points in a field is ...
*April 19, 2011*

**math please help**

use an inverse trig function to write theta as a function of x (There is a right triangle drawn. The hypotenuse is 2. Theta is the angle between the base and the hypotenuse. The base/adjacent side of theta is labeled(x + 1) The side opposite theta does not have a value.) Use ...
*March 30, 2011*

**trig**

use an inverse trig function to write è as a function of x (There is a right triangle. The hypotenuse is 2. è is the angle between the base and the hypotenuse. The base/adjacent side of è is (x + 1) The side opposite è does not have a value.) a) &...
*March 30, 2011*

**physics**

1)If I am to plot a graph of Force in Newtons vs. Stretch in meters, would the x axis be force or the stretch? 2) The data table has 3 columns: force in Newtons, position in m and displacement in m. Which one is used to plot the Stretch in meters? the position column or the ...
*March 16, 2011*

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