Tuesday
January 17, 2017

# Posts by Ivan

Total # Posts: 140

trigonometry
a yardstick, held vertically on a level surface, cast a shadow 1 foot 8 inch long. Find the tangent of the angles that the rays of the sun make with the horizontal
June 19, 2016

Science
In a heat engine, if 700 J of heat enters the system, and the piston does 400 J of work, what is the final internal (thermal) energy of the system if the initial energy is 1,200 J?
May 2, 2016

Chemistry
Question text Calculate the energy required to melt 21 g of ice at 0 oC. The molar heat of fusion for ice is 6.02 kJ/mol. Answer kJ
February 18, 2016

Chemistry
Hi, we have done an experiment in class where we have an equalibrium between (Co(H2O)6)^+2 + 4Cl^- <-> (CoCl4)^-2 + 6H2O where we added HCl dropwise until a colour change occured which changed the solution into a dark blue as the concentration of the Cholride ions ...
January 20, 2016

Chemistry
pepe is tasked with carefully measuring precisely one mole of aluminum. How should pepe go about completing this assignment?
January 11, 2016

Math
period of a 100 MHz FM radio were is roughly 1 X 10 to the negative 8th s. formulate a problem and solution.
January 3, 2016

math
Michelle has half of her investments in stock paying a 6% dividend and the other half in a stock paying 10% interest. If her total annual interest is \$680, how much does she have invested?
November 19, 2015

Chemistry - Energy: Phase Changes
Question text Calculate the energy required to melt 21 g of ice at 0 oC. The molar heat of fusion for ice is 6.02 kJ/mol. Answer kJ
November 12, 2015

Mathematics
The specific heat capacity of silver is 0.24 J/g °C. How many joules of energy are needed to warm 0.500 g of silver from 25.0°C to 27.5°C?
November 5, 2015

Math
6 Rows in all (2 more rows of 5 in each row)
October 6, 2015

Math
What is negative eight classified
September 17, 2015

Physics
According to Newton's 3/2 law, the total entropy change that occurs would be calculated by k*(1/2Ke)mv^2+degrees celcius giving you 1.3999898989898989899898
September 10, 2015

Math
A rectangle field has an area of 300 square meters and a perimeter of 80 meters. What are the length and width of the field? I really need help I don't know the answer.
July 11, 2015

math
Wow so do you seriously not know what the answer is Damon? Or are you just this stupid not to answer someone's question? Seriously . . . just wondering do you not know the answer?
July 11, 2015

psychology
Sorry don't know this answer please try again next time! :) LOL!
July 9, 2015

Language Arts
Not agreeable now! :(
June 4, 2015

That means when his nose grew with lies, he can just cut off his nose to make it short again and put it in the fireplace.
April 20, 2015

chem
Is there any monobasic solid acid with a molar mass of 120?
December 16, 2014

calculus
thx so much
December 10, 2014

calculus
lim(x tends to 3) (square root(x^2+7) -4) divided by (square root(x^2-8) -1) Pls help and list the steps. Thx
December 10, 2014

Stats
for a sample of n=20 how large a Pearson correlation is necessary to be statistically significant for a two tailed test
December 4, 2014

math
what **1/8 means?.
November 1, 2014

MATH
Fraction form 1/3 if changed Decimal form it is 1/3=0.331/3 if changed to Percent form it is 1/3=331/3% Is this correct? I just want make sure.
November 1, 2014

math
in math problem.how to change simplified fraction form 2/3 to decimal form and percent form
November 1, 2014

Math
63250/1000=63.25km 63.25km/7=9.04km 149*9.04=1346.96km so the answer is 1346.96km.
November 1, 2014

geomentry
Which angle is largest, A, B, or C
October 29, 2014

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

exam three americangov section 3
a b c d d d a b c a
September 12, 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

Science
Wait... maybe
April 10, 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 . WrirÃƒ© 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
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

Algebra
Section Solvers Lessons Answers Click here to see ALL problems on Quadratic-relations-and-conic-sections Question 812207: A gardener is putting a wire fence along the edge of his garden to keep animals from eating his plants. If he has 20 meters of fence what is the largest ...
December 1, 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

Physics
Vi=60m/s
September 19, 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

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