Thursday
May 28, 2015

Posts by Grace


Total # Posts: 432

statistics
On an exam whose scores followed a normal distribution, a student's z-score was +2. What percentage of students scored better than he did? (Use the 68-95-99.7 Rule.)
April 25, 2012

noun
if two dices are tossed together, the probability that the product will be less or equal to 18 what?
April 24, 2012

Chemistry
Are hybridized orbitals used to explain the fact that the four bonds in methane are equivalent? If not, what is?
April 16, 2012

Chemistry
The pH of a 0.100 M solution of an aqueous weak acid (HA) is 4.00. What would the Ka for the weak acid be?
April 16, 2012

physics
tommy builds a human sling shot that has an elastic constant of 4000 N/m. He puts his little sister in it and pulls it back for 5 meters. How much energy does his 25 kg sister have as she leaves the sling shot and how fast is she flying?
March 27, 2012

maths
Please I want to know how many litres make a metric tone.
March 25, 2012

STATISTICS
.868
March 19, 2012

physics
How would one plug the gravitational constant into an equation? To be honest, I'm having a hard time with the idea of the gravitational constant in general, but I need to solve an equation for the circular velocity of a galaxy. I know I need to multiply the gravitational ...
March 8, 2012

6th Grade Math
Simon went to the store to buy new school supplies. Simon spent 1/4 of his money on pencils and paper and 1/2 of his money on a backpack. If Simon has $12.50 leftover, how much did the backpack cost?
March 4, 2012

Math
There are 24 students in Mrs.Smith's 1st block class. 1/4 of the class passed the math test with an A. 12 students in the class passed the math test with a B. What percent of the students in the class passed the test?
March 1, 2012

Math
There are 24 students in Mrs.Smith's 1st block class. 1/4 of the class passed the math test with an A. 12 students in the class passed the math test with a B. What percent of the students in the class passed the test? ****** This is how I slove the problem, but I stuck in ...
March 1, 2012

physical science
120ml of a solution whose concentration is 30g/ml was diluted with distilled water by raising its volume to 160cm3. Calculate the concentration of the new solution.
February 25, 2012

Algebra 2
did you ever get this answer?
February 21, 2012

math
I have a question. I think I'm wrong, so I want to ask if it's right. If I do 3/4 x 1 5/6 x 7/4 x (-2 3/8) would the answer be negative?
February 6, 2012

Math
Given h(r) = 1/(r + 2), find: h(x^2) + 1 Thank You
February 4, 2012

math
the chef at a restaurant bought 37 pounds of salad for $46.25. how much did she pay for 1 pound of salad
January 30, 2012

chemistry
9.5 g Butane + 34.0 g Oxygen = 43.5 Then 43.5 - 28.7 g CO2 = 14.8 That is the answer: 14.8 g
January 22, 2012

Precalc
An ellipse has this Cartesian equation: ((x-2)/5)^2 + ((y-4)/3)^2 = 1 Find the focal radius Find the eccentricity Write the parametric equations for the ellipse Transform into the form, Ax^2 + By^2 + Cx + Dy + E = 0
January 20, 2012

Precalc
A hyperbola has this Cartesian equation: -((x-2)/5)^2 + ((y+1)/3)^2 = 1 A. Find direction in which it opens. Horizontal? B. Find the coordinates of the center. I think it's (-2,1) or (1,-2)? C. Find the slopes of the asymptotes: m=+- ?
January 20, 2012

Precalc
The figure shows the pre-image and first iteration for a set of transformations. If the iterations are carried on infinitely, the resulting fractal figure will have dimension given by Dimension=(LogN)/Log(1/r) It tells me to find N and r... What should I be looking for on the ...
January 19, 2012

Precalc
Thank you so so so much! I've been stuck on this for hours!
January 19, 2012

Precalc
The figure shows a 10 x 10 square centered at the origin. The darker-shaded square is the image of this square, dilated by a factor of 0.8 and rotated about the origin by exactly the number of degrees, , so that its corners touch the sides of the parent square. The corners of ...
January 19, 2012

4thGrade Math
11/15 feet long per piece. Or 8.8 inches.
January 19, 2012

Precalc
For this matrice, [[0.9cos(-30), 0.9cos(60), 2] [0.9sin(30), 0.9sin(60), 4] [0, 0, 1]] What is the rotation (in degrees) and is it clockwise or counterclockwise? I think it's 30 degrees clockwise...Is that right?
January 19, 2012

Precalc
I think it's [[2,4,6,4] [4,5,4,1] [1,1,1,1]] Is that correct?
January 19, 2012

Precalc
Write a 3 x 4 pre-image matrix for a kite with the points (2,4) (4,5) (6,4) and (4,1)
January 19, 2012

Precalc
I have: A. vector n= 3*vector i + 2*vector j + 5* vector k B. vector v= 7*vector i + 10*vector j + vector k C. 52.46 degrees And I'm not quite sure for D...
January 18, 2012

Precalc
Given the plane 3x+2y+5z=54 and the points P0(6, 8, 4)[on plane] and P1(13, 18, 5) [not on plane] A. Find vector n, a vector normal to the plane B. Find vector v from P0 to P1 C. Find the angle between vector n and vector v D. Find p, the scalar projection of vector v on ...
January 18, 2012

Precalc
Is it just ((6/11), (9/11), (2/11)) ?
January 18, 2012

Precalc
Yeah, sorry about that. There's a diagram to it and I wasn't sure how else to explain it.
January 18, 2012

Precalc
A line in space has the vector equation shown here. Fill in the blanks to find the position vector to the fixed point on the line that appears in the equation: vector r=(5+(6/11)d)vector i + (3+(9/11)d)vector j + (7+(2/11)d)vector k vector v= _____ vector i + _____ vector j + ...
January 18, 2012

Precalc
Ah. Alright, I think I understand.
January 18, 2012

Precalc
Thanks so much!
January 18, 2012

Precalc
I wish I could say that's why I don't understand this problem. But sadly, I still don't get it. Haha.
January 18, 2012

Precalc
In the problem before it says r(x)= (x^5 - c^5)/(x-c) Maybe it's referring to that? Does that help?
January 18, 2012

Precalc
By appropriate calculations, show that: lim r(x)=5c^4 (x->c)
January 18, 2012

Precalc
If α, β, and γ are direction angles for a vector in three dimensions and cos α = 0.6 and cos β = 0.7, find cos γ
January 17, 2012

Precalc
Suppose vector a is 3 units long, the magnitude of vector b is 1 units and cos (θ) = -0.3, where θ is the angle between the two vectors when they are placed tail-to-tail. What does the inner product of vector a and vector b equal?
January 16, 2012

world history
The dominant political philosophy in the Qin Dynasty was legalism.
January 7, 2012

Precalc
At the point were a line intersects a plane [with the equation (24x+32y+40z=480) and three points of A(5, 10, 1), B(6, 3, 6), and C(12, 1, 4)], the vector i-, vector j-, and vector k-coefficients of the line equal the corresponding values of x, y, and z for the plane. By ...
January 7, 2012

Precalc
Thank you (:
January 7, 2012

Precalc
Assume that points A(5, 10, 1), B(6, 3, 6), and C(12, 1, 4) are on a plane. Find vector AB and vector AC.
January 7, 2012

Precalc
Assume that points A(5, 10, 1), B(6, 3, 6), and C(12, 1, 4) are on a plane. Find vector AB and vector AC.
January 7, 2012

statistics
In 2005, about 233 million people in the United States were aged 14 or older. They consumed, on average, 2.23 gallons of alcohol per person. use scientific notation to estimate the total number of gallons of alcohol consumed by this age group.
November 23, 2011

Science
What do polar bears and automobiles have in common?
November 15, 2011

Math
Solve: ((10)/(x^2-3x+45))=x+1
November 13, 2011

Living environment
diffusion
October 27, 2011

Algebra 2 Problem
You own a computer store selling two types of laser printers. The first type,A, costs $141 and you make a $45 profit on each one. The second type,B, costs $110 and you make a $35 profit on each one. You expect to sell at least 100 laser printers this month and you need to make...
October 27, 2011

Physical Science
a 30 kg girl and a 25 kg boy face each other on a friction-free blades. The girl pushes the boy, who moves away at a speed of 1.0 m/s. The girls speed is __________m/s
October 25, 2011

environmental science
describe and compare total resource use per capita in developed and developing countries
October 21, 2011

math
in the month of May, ronald earned $4.36 in interest on his saving account. if his interest rate is 0.2%, how much money was in his account during the month?
October 18, 2011

Biology
Which internal organs of the fetal pig appear to have the greatest amounts of blood supplied to them? Why does this make sense?
October 17, 2011

Biology
Is the pancreas an exocrine or endocrine gland? Indicate the anatomical evidence on your fetal pig. What are its contributions to digestion and where are they added to the digestive tract?
October 17, 2011

earth
Which process could lead directly to the formation of pumice rock?
October 2, 2011

chemistry thank you
concentrated sulfuric acid has a density of 1.84 g/ml. calculate the mass in grams of 1.00 liter of this acid
September 27, 2011

physics!
The driver of a 1560 kg automobile traveling at 24 m/s on a leve, paved road hits the brakes to stop for a red light. determine the distance needed to stop the car if the coefficient of friction between the car tires and the road is .80 -one of the steps required of me to ...
September 23, 2011

algebra
how to figure 75% of 620
September 21, 2011

biology
explain why the synthesis of proteins, DNA and RNA requires energy. thanks :)
September 21, 2011

biology
thanks again!
September 21, 2011

biology
outline why energy is needed for each of these processes: a. the transport of sucrose in a plant b the transmission of an action potential along a nerve axon c. the selective reabsorption of glucose from a kidney nephron I'm not exactly sure how I'm supposed to answer ...
September 21, 2011

Biology
What are two major flaws in the Phylogenetic Tree System?
September 20, 2011

chemistry
thanks
September 15, 2011

chemistry
in emission spectrum which one has a highest frequency and highest energy is it blue red or violet? which one is the lowest?
September 15, 2011

math
what will i answer if the question is " identify the symmetry" is it even/odd FUNCTION or Even/odd SYMMETRY?
September 15, 2011

chemistry
yes, it's all about emission spectrum..
September 15, 2011

chemistry
does elements with low energy have high frequency?
September 15, 2011

Chemistry
What is the Wavelength( in nm) of the least energetic spectral line in the infrared series of the H atom? I don't understand how to find the least energetic spectral line?
September 10, 2011

physics
A man pushing a mop across a floor causes the map to undergo two displacements. The first has a magnitude of 200 cm and makes an angle of 120° with the positive x axis. The resultant displacement has a magnitude of 240 cm and is directed at an angle of 60.0° to the ...
September 10, 2011

Chemistry
Covalent bonds in a molecule absorb radiation in the IR region and vibrate at characteristic frequencies. a) The C---O bond absorbs radiation of wavelength 9.6um. What frequency (in s-1) corresponds to that wavelength? b) The H---Cl bond has a frequency of vibration of 8....
September 8, 2011

Chemistry
I don't understand that process, since the answer for the meters is supposed to be 316m
September 7, 2011

Chemistry
An AM station broadcasts rock music at "950 on your radio dial" Units for AM frequencies are given in kilhertz(kHz). Find the wavelength of the station's radio waves in meters, nanometers, and angstroms.
September 7, 2011

Chemisty
Calculate the energy in radiation of wavelength 550 nm carried by 1) one photon 2) 1 mol of photons
September 6, 2011

Chemisty
Calculate the energy in radiation of wavelength 550 nm carried by 1) one photon 2) 1 mol of photons
September 6, 2011

SAT math
If five distinct lines lie in a plane, then at most how many distinct points can lie on two or more of these lines? 6 7 8 9 10.
August 19, 2011

algebra
TGIF. Chris and Terry have been trying to live within their budget but miss going out to dinner on Friday nights. They decide not to spend any nickels or quarters they receive as change for a month and save these in a jar. At the end of the second week they have a total of 165...
July 17, 2011

math
Write the equation of the line satisfying the given condition. Parallel to y = (2/3)x +1 and passing through the point (0, -3). (Hint: Parallel lines have the same slope
July 17, 2011

algebra
Write the equation of the line satisfying the given condition. Perpendicular to y = 4x + 2 and passing through the point (0, -4) (Hint: Slopes of non-vertical perpendicular lines are negative reciprocal of each other.)
July 17, 2011

algebra
Solve the inequality algebraically. Graph your solution on a number line.
July 17, 2011

math
Suburban Population. The following charts show the populations for two suburbs from 1980 to 1990, where x = 0 correspond to 1980, x = 2 correspond to 1982, and so on. Year x Suburb 1 y Year x Suburb 2 y 0 12,690 0 23,112 2 12,071 2 23,893 4 13,463 4 24,674 6 13,867 6 25,455 8 ...
July 17, 2011

mathh
The average (arithmetic mean) of x and y is m, where m does not equal to 0. What is the average (arithmetic mean) of x, y, and z? a.)m b.)4/3m c.)3/2m d.)5/3m e.)2m
July 10, 2011

math
A flat stone is thrown horizontally across a frozen lake. If the stone decelerates at 2.5 meter per second squared, what is the coefficient of friction between the stone and the ice?take g equals 10 meter per second
June 18, 2011

Science (Chemistry)
The Average density of Earth is 5.52g/cm^3. What is its density in a. kg/m^3 b. lb/ft^3. Please help me set up these equations. Thank you!
June 13, 2011

physics
What is force of attraction between two students of mass 20kg,10meters apart?
June 5, 2011

physics
What is force of attraction between two students of mass 20kg,10meters apart?
June 5, 2011

science
i need 3 examples of supension. any suggestions?
May 11, 2011

maths
Oh sorry! Thanks
May 8, 2011

maths
The mass of a particular substance is known to grow exponentially at a rate of 0.5% per hour. Its initial mass was 25 grams and, after t hours, it weighed 31 grams. The equation modelling this growth is 25×1.005 t  =  31. Use the method of ...
May 8, 2011

chemistry
Which of the following statements are true? Fusion reactions result in nuclei with higher Z. To keep a nuclear power plant going, a chain reaction must be maintained. Nuclear fusion produces no long-lived radioactive by-products. The Sun is a nuclear fusion reactor.
April 14, 2011

Algebra 1
What is 1/9+1/y=4/y
April 5, 2011

physics
A car is travelling at 42.4 km/h on a flat highway. The acceleration of gravity is 9.81 m/s^2. If the coefficient of friction between the road and the tires on a rainy day is 0.125 what is the minimum distance for the car to stop? Answer is metres
April 2, 2011

maths
find in implicit form, the general solution of the differential equation dy/dx = 2(e^x-e^-x)/y^2(e^x+e^-x)^4
March 24, 2011

chemistry
Why sodium oxide is a solid at room temperature whereas sulfur trioxide is a low boiling point liquid?
March 12, 2011

Chemistry
The boiling ponit of phophine is -85 oC, whilst of ammonia in the same group is -33.5 oC, how can we account for this difference in BP?
March 12, 2011

chemistry
sorry if that was confusing
March 2, 2011

not really sure
What is the mass of a mole of Sodium Carbonate?
March 2, 2011

Life orientation
Which two labour laws protect the employee against discrimination in the work place?
February 21, 2011

Calculus
Find the derivative of 4e^x+x^3
February 10, 2011

Calculus
Derivative of: (t^7+t^8-1)/t^9
February 9, 2011

Chemistry
FeSCN2+ -> Fe3+ + SCN- Solution is initially dark red. If some Ag+ is added to form AgSCN. what happens to position of equilibrium? what happens ot the color?
February 8, 2011

Calculus
Find the equation of the line tangent to the graph of f at (1,1) where f is given by f(x)=2x^3-2x^2+1
February 8, 2011

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