Monday

October 20, 2014

October 20, 2014

Total # Posts: 104

**statistics**

Scores on a national writing exam are approximately normally distributed, with a mean of 490 and a standard deviation of 20. Consider random samples of size 25 from the population of test takers. describe the sampling distribution of a sample mean. shape mean= standard ...
*October 17, 2014*

**chem**

Which of the following ions contains lone pair of electrons at the central atom? A) SO4 2- B) NO3 - C) IO3 - (Is there any ways without drawing the diagrams and I could still able to figure out the answer???) Thx very much
*October 2, 2014*

**Material Behavior**

The energy-separation curve for two atoms, a distance, r, apart is: U(r)=−A/r^m+B/r^n Derive and expression for the stiffness of the bond at the equilibrium spacing, in terms of A, B, m, n, and r0. S=dF/dr at r=r0:
*September 29, 2014*

**Material Sciences**

steel core, what is the thermal stress in the aluminum shell when the system is heated from the unstressed state (20∘C) to 180∘C? Consider only deformations in the axial directions. Give your answer in MPa αAl=23.6×10−6K−1 EAl=70GPa α...
*September 27, 2014*

**Material Sciences**

The energy-separation curve for two atoms, a distance, r, apart is: U(r)=−A/r^m+B/r^n Derive and expression for the stiffness of the bond at the equilibrium spacing, in terms of A, B, m, n, and r0. S=dF/dr at r=r0:
*September 27, 2014*

**Physics**

The statically-indeterminate composite beam AB of length 2L is fixed at A (x=0) and is simply supported at B (x=2L). The beam is composed of a core of modulus E0 of constant square cross section of dimensions 2h0×2h0 bonded inside a sleeve of modulus 2E0 and constant ...
*August 26, 2014*

**math**

A gumball machine contains orange, yellow and purple gumballs. The probability of getting an orange ball is 3/4 and the probability of getting yellow ball is1/6. What is the probability of getting a purple ball?
*May 2, 2014*

**Algebra**

List all asymptotes (both horizontal and vertical) of the rational function: f(x)=(10x−3)/(8−7x)
*April 7, 2014*

**Dynamics**

A linear spring of stiffness k is designed to stop the 20-Mg railroad car traveling at 8 km/h within 400mm after impact. Find the smallest value of k that will produce the desired result.
*March 17, 2014*

**Physics**

A linear spring of stiffness k is designed to stop the 20-Mg railroad car traveling at 8 km/h within 400mm after impact. Find the smallest value of k that will produce the desired result.
*March 17, 2014*

**Dynamics**

The man slides the 100-kg crate across force of 200 N. If the crate was initially at rest, how far will the crate move before its speed is 1 m/s? The coefficient of kinetic friction between the crate and the floor is 0.18. The man is pulling the crate at a 20 degree angle.
*March 17, 2014*

**Math**

Thank you Ms. Sue I get the same answer. The problem is that teacher offer this answers: a. 29 cm b. 28 cm c. 27 cm d. 33 cm What did we do wrong?
*March 8, 2014*

**Math**

The length of a rectangle is 3 cm less than 4 times its width. The perimeter is 74 cm. Find the length
*March 8, 2014*

**Chemistry 2**

ok thank you, exactly what i needed to know .
*March 3, 2014*

**Chemistry 2**

For the fist order reaction A <-> B, calculate the t1/2(half life) and k(rate constant) and also fill in the blanks. A-Concetration t-time 20 0 10 ? 5 40 sec 3 ? ? 500 sec t1/2=? k=?
*March 3, 2014*

**Chemistry 2**

ok thank you, whats the formula to find the time of the missing blanks in the question?
*March 3, 2014*

**Chemistry 2**

Thanks man that makes so much clearer. i posted another question similar to this but its a first order reaction. would that change how you work it or is it done the same?
*March 3, 2014*

**Chemistry 2**

For a second order reaction A <--> B, calculate the t1/2 (half life) and the k(constant) and also fill in the blanks. A (concentration) t(time) 20 0 sec 10 ? 5 40 sec 3 ? ? 200 sec t1/2=? k=?
*March 3, 2014*

**Chemistry 2**

ok i got that now thank you. how will i find the answer for the blanks in the time? is there a formula for it?
*March 3, 2014*

**Chemistry 2**

what do you mean?
*March 3, 2014*

**Chemistry 2**

For the fist order reaction A <-> B, calculate the t1/2(half life) and k(rate constant) and also fill in the blanks. A-Concetration t-time 20 0 10 ? 5 40 sec 3 ? ? 500 sec t1/2=? k=?
*March 3, 2014*

**Chemistry 2**

Thanks man both answers you have answered for me have checked out to mine that i have got.
*March 3, 2014*

**Chemistry 2 **

When we mix 25.0 mL, 2.0 M BaCl2 with 25.0 mL, 3.0 M Na2SO4 what is the balanced equation? What is the ionic equation? what is the net ionic equation?
*March 3, 2014*

**Chemistry 2**

For the reaction: 2A + 3B <--> 4C Kinetic data are as follows A B time needed 10mL 5mL 720 seconds 20mL 5mL 180 seconds 20mL 10mL 90 seconds 30mL 20mL ?? The rate of the equation is?
*March 3, 2014*

**Chemistry 2**

Thanks man i appreciate it
*March 3, 2014*

**Chemistry 2**

What is the molarity of 50.0 mL solution of aluminum sulfite that contains 80.0 g of this salt? (Al=27.0, S=32.0,O=16.0)
*March 3, 2014*

**Math**

If a varies jointly as b and c, and if a = 100 when b = 5 and c = 25, find a when b = 12 and c = 60
*February 20, 2014*

**Math**

Thanks Reiny
*February 20, 2014*

**Math**

Solve the equation: |6x - 2| = |3x + 1|
*February 20, 2014*

**physics**

Participants in a road race take water from a refreshment station and throw their empty cups away farther down the course. If a runner has a forward speed of 6.20 m/s, how far in advance of a garbage pail should he release his water cup if the vertical distance between the lid...
*July 7, 2013*

**Physics**

Mary walks west at 2.0m/s for 15 seconds, then north at 3.0m/s for 2o seconds and then east at 4.0m/s for 0 seconds. What is her displacement answer is (108m(N56 DEgrees E)
*July 4, 2013*

**Physics**

At that height, you can evaluate the gradient of the normal(which is actually -2.5). then youu find the angle between the horizon and the normal at that height.Let the force acting from the surface along the normal as F.Decompose the force into F_x(parallel to the horizon) and...
*June 25, 2013*

**math**

NELSON GOT A PACK OF 12 PENCILS. HE TOOK 3 PENCILS TO PUT IN HIS DESK AT SCHOOL AND 2 PENCILS TO PUT IN HIS LOCKER AT SCHOOL. WHAT IS THE FRACTION OF TOTAL PENCILS THAT NELSON TOOK TO SCHOOL?
*January 9, 2013*

**math**

On a sunny afternoon. The stratosphere tower casts a shadow that is 140 meters long. At the same a nearby flagpole that is 10 meters tall cast a shadow that is 4 meters long . WrirÃƒÂ© silve the problem
*December 12, 2012*

**Physical Science**

A truck whose bed is 2.5m long, 1.5m wide, and 1m high is delivering sand to a construction site. How many trips must the truck make to deliver 7? cubic meters of sand? Plese explain your answer.
*November 7, 2012*

**Physical Science**

A truck whose bed is 2.5m long, 1.5m wide, and 1m high is delivering sand to a construction site. How many trips must the truck make to deliver 7? cubic meters of sand? Plese explain your answer.
*November 7, 2012*

**College Physics**

This answers is wrong don't use please.
*July 6, 2012*

**physics**

A small cork with an excess charge of +7.0 µC is placed 0.16 m from another cork, which carries a charge of −3.2 µC. What is the magnitude of the electric force between the corks? The Coulomb constant is 8.98755 × 10 9 N · m2 /C 2 . Answer in ...
*February 26, 2012*

**physics**

Calculate the net charge on a substance consisting of a combination of 8.9 × 10 13 protons and 4.4 × 10 13 electrons. Answer in units of C
*February 26, 2012*

**physics**

A negatively charged balloon has 4.5 µC of charge. How many excess electrons are on this balloon? Answer in units of electrons
*February 26, 2012*

**physics**

An unclothed student is in 24 ◦ C room. If the skin temperature of the student is 37 ◦ C, how much heat is lost from his body in 6 min, assuming that the emissivity of the skin is 0.83 and the surface area of the student is 1.5 m2 . The Stephan-Boltzmann constant ...
*February 19, 2012*

**Physics**

During a certain thermodynamic process a sample of gas expands and cools, reducing its internal energy by 3690 J, while no heat is added or taken away. How much work is done during this process?
*February 19, 2012*

**English**

I need help on; how to contrast Walt Whitman perspective of America with the perspective that the members of Occupy Wall Street and the the Tea Party movement have about America.?
*January 7, 2012*

**Pre-calculus**

2^(x)/(1-2^(x))=3
*December 12, 2011*

**physical science**

absolute zero is the same as
*November 27, 2011*

**chemistry**

hey! help me
*November 6, 2011*

**chemistry**

in saturated sugar solutions what is the solute? what is the solvent?
*November 6, 2011*

**phy**

A 3.50 kg block on a smooth tabletop is attached by a string to a hanging block of mass 2.80 kg. The blocks are released from rest and allowed to move freely. 1-Is the tension in the string greater than, less than, or equal to the weight of the hanging mass? 2-Find the ...
*July 18, 2011*

**phy**

correction i- 92 mi/h ii- 0/15 m iii- 803 N
*July 16, 2011*

**phy**

A major-league catcher gloves a 92 {\rm mi}/{\rm h} pitch and brings it to rest in 0.15 {\rm m}. 1-If the force exerted by the catcher is 803 {\rm N}, what is the mass of the ball?
*July 16, 2011*

**chemistry**

1-why should the maximum percent yield never be above 100%?
*July 16, 2011*

**history**

2. Why did European economic practices and financial institutions (trading companies, banks, investments, creation of global markets) weaken Middle Eastern and Asian economies and upset local politics? 3. How did countries or empires in the Middle East and Asia attempt to ...
*June 8, 2011*

**history**

How did European explorations and commercial activities in the early modern period affect regions of the Middle East and Asia?
*June 8, 2011*

**math**

10 degrees of circle in fraction
*May 10, 2011*

**nalya sec sch**

do people accomplish more to do things in thiere own way
*April 25, 2011*

**Geometry**

How large is an angle whose supplement is three times its complement?
*January 18, 2011*

**Geometry**

If we want to find the height of an object like a flagpole, what type of triangle do I use?
*January 18, 2011*

**Geometry**

An alloy of copper is 10% copper and weighs 25 pounds. A second alloy is 18% copper. How much (to the nearest tenth lb.) of the second alloy must be added to the first alloy to get a 13% mixture.
*January 18, 2011*

**Geometry**

Find the area of the bedroom in square feet of 11' x 13' 10"
*January 18, 2011*

**Geometry**

If a rectangular lot measures 120 ft. x 80 ft., and 10 foot set backs are required from each lot line, how much area is left? If a kennel for 50 dogs requires 12,500 square feet, how many dogs can be accommodated in the small rectangle?
*January 18, 2011*

**Geometry**

Mr. Thompson has been asked to add storage space to a garage. He estimates 6 square feet per individual will be required to meet the needs of 12 people. If the storage space is 15% of the total amount of space required, how much total space does Mr. Thompson have?
*January 18, 2011*

**Geometry**

Two angles are complementary. One contains 20° more than the other. Find both angles.
*January 18, 2011*

**Geometry**

If the boy is 4' 9" tall and his shadow is 6 ft. and the shadow of the flagpole is 19 ft., determine the height of the flagpole (to the nearest tenth).
*January 17, 2011*

**Geometry**

The sides of a triangular lot are represented by x, 2x, and 3x + 2. Find each side if the perimeter is 362 feet. What are the 3 lengths?
*January 16, 2011*

**Geometry**

A square measures 8 inches on each side. What is its area rounded off to the nearest whole number. (Note: 1 inch ≈ 2.54 cm)
*January 16, 2011*

**Geometry**

A trapezoid has an altitude of 12 cm. Its parallel sides measure 10 and 8 cm, respectively. What is it's area?
*January 16, 2011*

**Geometry**

Compute the area of the triangle. (Express answer in cm2) h = 6 cm b = 12 cm a = How many cm2?
*January 16, 2011*

**Geometry**

Compute the area of a triangle with sides. 15 × 15 × 18 a = How many square units?
*January 16, 2011*

**Geometry**

A lot is in the shape of a trapezoid. The sum of the bases is 180 feet. If the area of the lot is 8,100 square feet, what is the distance across the lot, i.e., the altitude of the figure? The altitude of the trapezoid is how many feet?
*January 16, 2011*

**Geometry**

a = 12 ft. b = 8 ft. a = How many sq. ft. ?
*January 16, 2011*

**Geometry**

a = 12 cm b = 14 cm h = 8 cm. Compute the area. How many cm2?
*January 16, 2011*

**Geometry**

Find the area of the following circle. r = 9 yd. a = How many square yards?
*January 16, 2011*

**Geometry**

Find the area of the following ellipse (round to nearest tenth). a = 9 in.; b = 8 in. a = How many sq. in.?
*January 16, 2011*

**Geometry**

Find the area of the following ellipse (round to nearest tenth). 2a = 10 cm; 2b = 24 cm. a = How many cm2?
*January 16, 2011*

**Geometry**

A contractor is pouring a concrete driveway. The perimeter is 108 ft. What length will the driveway be if the width is 12 ft.? How many feet is the Drive Way?
*January 16, 2011*

**Geometry**

A gardener is installing a circular garden. The radius of the circle 28 feet. He needs to know the circumference in order to buy materials for the edging. What is the circumference if he uses = 22/7. The circumference is ?
*January 16, 2011*

**Geometry**

Find the area of the following circle. ( = 3.14; round answer to the nearest whole number). Circumference = 120 cm. (Hint: Find r from C = 2r (round r to tenths); then find area).
*January 16, 2011*

**calculus5**

I understand what you guys think I am a soldier on duty and I have to turn these in I am runnning out of time and I need help thanks
*November 28, 2010*

**calculus5**

(y^2+2)^3=x^4y+e^2 find dy/dx using differentiating implicity
*November 28, 2010*

**calculus4**

2y^3-y=7-x^4 find dy/dx using differentiating implicity
*November 28, 2010*

**calculus3**

x^2/3+y^2/3=5 find dy/dx using differentiating implicity
*November 28, 2010*

**calculus2**

x^2+2y^2-11=0 find dy/dx using differentiating implicity
*November 28, 2010*

**calculus1**

x^5-5y=6-x find dy/dx using differentiating implicity
*November 28, 2010*

**Calculus**

6x-3y=4 find dy/dx using differentiating implicity
*November 28, 2010*

**Physics**

Four identical 12µC charges are placed at the corners of a square of sides 44 cm, with one additional 12µC charge placed at the center. Find the electric potential at the midpoint of one of the sides.
*November 12, 2010*

**Calculus 1**

Calculate f'(-1) f(x) = x^7 * h(x) h(-1) = 5 h'(-1) = 8 Answer is 27, but I got no idea how to get there.
*October 28, 2010*

**french**

"How many days are there in the month of october?"
*October 28, 2010*

**3rd math homework**

6-4=2 2+4=6 you can use other numbers too 6-5=1 1+5=6 etc.
*October 28, 2010*

**Math. **

420cal = 2.25 cans ? cal = 1can To find the number of calories we just do the cross product, so: 420cal x 1can / 2.25cans = ? cal 420cal/2.25cans = 186.6667cal
*October 28, 2010*

**English check**

Lasted only about a century as a way of life but has persisted as an influence
*August 24, 2010*

**Electronic Timing inc**

good
*March 30, 2010*

**sunshine math-4**

mark hid a 10 bill inside his favorite book. he forgot the pages where he hid it. is the sum of the pages where the bill is hidden is 177, on what pages will mark find his money
*March 16, 2010*

**math**

use the digets 2,4,6,and 8 to create an expression with a value of 2
*October 6, 2009*

**Alegebra 1**

1/35
*September 8, 2009*

**Stoichiometry**

6 NaOH + 2 Al ---> 2 Na3AlO3 + 3 H2 How many moles of NaOH are required to produce 3 g of hydrogen?
*March 22, 2009*

**Calculus**

find the x-coordinate of the point P on the parabola y=1-x^2 for 0<x<1 where the triangle that is enclosed by the tangent line at P and the coordinate axes has the smallest area.
*November 6, 2008*

**writing**

Is this a run-on: Martha moans and groans upon getting in the morning she sounds like a crazy woman.
*June 25, 2008*

**science**

eukaryote
*May 27, 2008*

**eukaryoyoinacrosticpoem**

into
*May 27, 2008*

**READING**

HELP ON HOW TO START A 5TH GRADE BOOK REPORT
*March 16, 2008*