Saturday

May 23, 2015

May 23, 2015

Total # Posts: 962

**Chemistry**

A standard solution with a FeSCN2+ concentration of 1.55x10^-4M has a percent transmittance (%T) of 18.8%. Another solution of unknown FeSCN2+ concentration has a percent transmittance of 44.8%. A) Calculate the absorbance (A) of each solution. B) Using the absorbances ...
*February 26, 2014*

**Chemistry**

5.00 mL of 2.00x10^-3M Fe(NO3)3 is mixed with 4.03 mL of 2.00x10^-3M NaSCN and 1.08 mL of 0.1M HNO3, for a total volume of 10.11 mL. a) What is the initial concentration of the Fe(NO3)3 in the mixed solution? b) What is the initial concentration of the NaSCN in the moxed ...
*February 26, 2014*

**Math**

Interest is a concept familiar to most people: every credit card in existence has a term called annual percentage rate (APR), which is an interest rate. Suppose you charged $1,000 to a credit card that has a minimum payment each month equal to the interest owed. Can you figure...
*February 18, 2014*

**Math**

The formula for simple interest is where I is the amount you will pay in interest, r is the rate at which interest will accrue, P is the principal (amount borrowed), and m is the number of times the interest is applied. To solve for the interest rate of your credit card, you ...
*February 18, 2014*

**Math**

Gabe is the human resource manager for the Advanced Scientific Research Lab. He has to record the heights (in centimeters) and weights (in pounds) for each of the scientists in the lab. Height distribution (cm): 178, 163, 174, 186, 154, 167, 167, 181, 159, 165, 177, 191, 158 ...
*February 18, 2014*

**AP chem**

Mostly just setting up my reaction to use for each problem
*February 5, 2014*

**AP chem**

Consider the titration of 50.00 ml .250 M HBr with .100 M Ba(OH)2. What is the pH after the following additions of Ba(OH)2 to the 50 ml of hydrobromic acid? 0 ml. 15 ml. 25 ml. 50ml. 51ml.
*February 5, 2014*

**programming**

using pseudocode debug the following 3 programs // A high school is holding a recycling competition // This program allows a user to enter a student's // year in school (1 through 4) // and number of cans collected // Data is entered continuously until the user wants to ...
*January 13, 2014*

**Physics**

I got it!!! Thank you!!!
*December 24, 2013*

**Physics**

I dont understand it, can you please explain it to me?.. Thanks
*December 24, 2013*

**Physics**

I think it is. and it's not one person, we study in a group. Thank You.
*December 24, 2013*

**Physics**

A pilot, whose mass is 91.0 kg, makes a loop-the-loop in a fast jet. Assume that the jet maintains a constant speed of 125 m/s and that the radius of the loop-the-loop is 0.478 km. What is the apparent weight that the pilot feels (i.e., the force with which the pilot presses ...
*December 24, 2013*

**Physics**

Thank you so much Elena!!
*December 24, 2013*

**Pre-Calc**

Using the difference for formula, find the tan 255. Step by step would be appreciated
*December 18, 2013*

**Math Quiz**

Math Quiz please help fast Write the following ratio in simplest form: 32 min:36 min (1 point) 8:9 8:36 32:9 128:144 2. Marie saved $51. On Wednesday, she spent $8 of her savings. What ratio represents the portion of her total savings that she still has left? (1 point) 43:8 8:...
*December 12, 2013*

**Maths**

Will it be 16x^2-40x+25
*November 18, 2013*

**Maths**

(4x-5)^2
*November 18, 2013*

**Maths**

(5x+4)(5x-4)=
*November 18, 2013*

**physics**

You apply a potential difference of 5.00 V between the ends of a wire that is 2.65 m in length and 0.654 mm in radius. The resulting current through the wire is 17.6 A. What is the resistivity of the wire?
*October 20, 2013*

**Math**

Carla and Candice left from the same place at the same time and rode their bikes in the same direction along a straight road . Candice biked at an average speed that was three-quarters of Carla's average speed. After 2 hours they were 28 miles apart. What was the average ...
*October 7, 2013*

**Math**

The area of each trapezoid is 3 times the area of one triangle. The area of one triangle is six square units. What is the total area of the figure in square units?
*September 23, 2013*

**Algebra word prob**

If you graph the table of values and draw a line through the coordinates, the graph will look like a parabola. Thus the equation is quadratic. Since you don't have a graphing calculator, I will give you the resulting a/b/c values that it comes up with, but the rest is for ...
*September 10, 2013*

**Math**

2. True or false. Suppose the slope of a straight line L is -3/4 and P is a given point on L. If Q is a point on L lying 2 units to the right of P, then Q is situated 3/2 units below P. Prove why.
*August 27, 2013*

**physics **

The Hyperloop is a hypothetical new fast transport system between cities, which works by launching pods that carry people through a very low air pressure tunnel. The Hyperloop reduces friction between the pods and the tunnel by supporting the pod on a cushion of air. This air ...
*August 22, 2013*

**Statistics**

Hola ¿Cuál es el P - value en este problema que escribiste?
*July 29, 2013*

**Math**

A circle of radius 1 is drawn in the plane. Four non-overlapping circles each of radius 1, are drawn (externally) tangential to the original circle. An angle γ is chosen uniformly at random in the interval [0,2π). The probability that a half ray drawn from the centre...
*June 24, 2013*

**Math**

There are 100 runners, each given a distinct bib labeled 1 to 100. What is the most number of runners that we could arrange in a circle, such that the product of the numbers on the bibs of any 2 neighboring runners, is less than 1000?
*June 23, 2013*

**Math**

γ is a permutation on eight elements, though you are not told which permutation it is. If γ is applied to an 8-element set, what is the minimum number of additional times we must apply γ to the resulting set in order to guarantee the set is back in its original ...
*June 18, 2013*

**Physics 1**

A body of mass 6kg moving at 8m/s collides with a stationary body of mass 10kg and sticks to it. Find the speed of the composite body immediately after the impact.
*June 10, 2013*

**Math (Algebra)**

Thanks Steve!
*May 21, 2013*

**Math (Algebra)**

f(x) is a cubic polynomial that satisfies f(1)=f(2)=f(3)=4 and f(0)=0. What is the value of f(7)?
*May 21, 2013*

**Math (Probability)**

Please tell the answer. I'm not able to get it. Thanks.
*May 21, 2013*

**Math (Probability)**

Bret and Shawn are playing a game where each turn the players roll a 20-sided die fair and then add the number they get to their score. The winner is the player with the highest score at the end of the game (there may be a tie). Before the last turn, Shawn is winning by 10 ...
*May 21, 2013*

**Math (Algebra)**

A number is called algebraic if there is a polynomial with rational coefficients for which the number is a root. For example,√2 is algebraic because it is a root of the polynomial x^2−2. The number √2+√3+√5 is also algebraic because it is a root ...
*May 21, 2013*

**Physics**

A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long in seconds does it take for the door to fully...
*May 21, 2013*

**Math (Combinatorics)**

Six boxes labeled 1,2,…,6 are arranged in a line. Seven identical balls are to be placed into the boxes such that for any 1 ≤ k ≤ 6, there are at least k total balls amongst boxes 1,2,…k. How many different placements of the balls into the boxes are ...
*May 21, 2013*

**math**

or 9√970/500.
*May 20, 2013*

**math**

It's 0.5606068140863.
*May 20, 2013*

**Physics**

A 15 kg, 1m wide door which has frictionless hinges is closed but unlocked. A 400 g ball hits the exact middle of the door at a velocity of 35 m/s and bounces off elastically, thereby causing the door to slowly swing open. How long in seconds does it take for the door to fully...
*May 20, 2013*

**Geometry**

Perimeter of Rectangle = 2L + 2W where: L = length, and W = width Perimeter = 2(8) + 2 (6)= 28 inches Area of Rectangle = L x W Area = (6in)(8in) = 48 inches squared.
*May 20, 2013*

**heeelp MATH**

Yes please Reiny. It would help me a lot. Thanks! :)
*May 16, 2013*

**Math (Geometry)**

ABC is a triangle with a right angle at A. M and N are points on BC such that AM is the altitude, and AN is the angle bisector of ∠BAC. If CN/NB=21, what is CM/MB?
*May 16, 2013*

**Math (Geometry)**

ABC is a triangle with a right angle at A. M and N are points on BC such that AM is the altitude, and AN is the angle bisector of ∠BAC. If CN/NB=21, what is CM/MB?
*May 15, 2013*

**Math (Geometry)**

Thanks hans!
*May 15, 2013*

**Math (Geometry)**

A point P is given outside of a circle Γ. A tangent from P to Γ touches Γ at T with PT=45. A line from P cuts Γ at the 2 points A,B. If PA=25, what is the length of PB?
*May 15, 2013*

**Math (Geometry)**

ABCD is a parallelogram with side lengths AB=15,BC=10 and ∠ADC=75∘. A point P in the interior of the parallelogram is chosen such that ∠APD+∠CPB=180∘. What is the measure (in degrees) of ∠PAD+∠PCB?
*May 15, 2013*

**Math (Probability)**

When Lino submitted an essay for his English class, it was 9 pages long. Lino's essay had errors on pages 2 and 7. If the teacher chose 3 pages uniformly at random to read, then the probability that she didn't read any of the pages with errors can be expressed as a/b ...
*May 15, 2013*

**Math - Maximizing Logarithm**

x and y are positive values satisfying x + y = 1/4. When ln(y^2+4xy+7) attains its maximum (subject to the given constraint), what is the value of 1/xy?
*May 13, 2013*

**algebra**

12(3+y)=5(2y+8)
*May 11, 2013*

**math**

the class room had 100 students.in 200, there were 6 few men than there were woman.how man women were in the classroom in 2010?
*May 9, 2013*

**accounting**

A company was recently formed with $ 50,000 cash contributed to the company by stock-holders. The company then borrowed $ 20,000 from a bank and bought $ 10,000 of supplies on account. The company also purchased $ 50,000 of equipment by paying $ 20,000 in cash and issuing a ...
*May 7, 2013*

**Pre Algerbra**

I invested $3,000, part at 2% and the rest at 5% simple interest. After 1 year, I earned a total of $117 in interest. How much did I invest at each rate?
*April 25, 2013*

**math**

0.941
*April 21, 2013*

**physics**

A radio station on the surface of the earth radiates an EM-wave with an average total power of 50 kilo-watts. Assuming the transmitter radiates equally in all directions (not in real life), find the amplitudes Emax and Bmax detected by a satellite at a distance of 100km from ...
*April 15, 2013*

**physics**

Four acrobats of mass 61.0 kg, 68.0 kg, 62.0 kg, and 55.0 kg form a human tower, with each acrobat standing on the shoulders of another acrobat. The 61.0-kg acrobat is at the bottom of the tower. If the area of each of the 61.0-kg acrobat's shoes is 370 cm2, what average ...
*April 4, 2013*

**Physics**

For safety in climbing, a mountaineer uses a nylon rope that is 55 m long and 0.9 cm in diameter. When supporting a 88-kg climber, the rope elongates 1.4 m. Find its Young's modulus.
*April 4, 2013*

**physics**

A window washer is standing on a scaffold supported by a vertical rope at each end. The scaffold weighs 192 N and is 3.4 m long. What is the tension in each rope when the 708-N worker stands 2.40 m from one end? Smaller tension: ___N Larger tension: ___N
*April 4, 2013*

**Chemistry**

A 7mL triprotic acid was analyzed and found to contain 0.2572 grams of acid, evidence of phosphate group. Find the molecular weight of the acid, and identify acid. Thank you.
*April 3, 2013*

**physics**

I am helping my friend move into his new apartment. During the move, we have to load boxes into the back of his truck. To make it easier to load them, we've set up a metal ramp so that we can slide the boxes up to the deck of the truck. The box shown in the figure has a ...
*April 2, 2013*

**western illinois**

102 = 3.14 x 42.25 x h solve for h
*March 30, 2013*

**Calculus**

The volume of the 3-dimensional structure formed by rotating the circle x^2 + (y-5)^2 = 1 around the x-axis can be expressed as V = a\pi^2. What is the value of a?
*March 27, 2013*

**Physics**

Every once in a while a bird will get hit by a baseball during a baseball game. The longest home runs in baseball land about 500 feet (which is 152.4 meters) from home plate. If these balls leave the bat at a 45 degree angle to maximize their distance, what is the minimum safe...
*March 27, 2013*

**Trigonometry**

ABC is a right triangle with AB = 2, BC = 3\sqrt{5}, AC = 7 and \angle ABC = 90^\circ. If \cos \angle BAC = \frac{a}{b}, where a and b are coprime positive integers, what is the value of a + b?
*March 27, 2013*

**Geometry**

Determine the number of subsets of A=\{1, 2, \ldots, 10\} whose sum of elements are greater than or equal to 28 .
*March 26, 2013*

**Geometry**

ABC is an acute triangle with \angle BCA = 35 ^\circ. Denote the circumcenter of ABC as O and the orthocenter of ABC as H. If AO=AH, what is the value of \angle ABC (in degrees)?
*March 26, 2013*

**Geometry**

ABC is an isosceles triangle where AB = AC and BC = 60. D is a point on BC such that the perpendicular distance from D to AB and AC is 16 and 32, respectively. What is the length of AB?
*March 26, 2013*

**physics**

A cargo plane is moving with a horizontal velocity of vx = +225 m/s at a height of y = 920 m above level ground as shown in the figure below when it releases a package. Ignoring air resistance, how much time will it take the package to reach the ground? (Express your answer to...
*March 26, 2013*

**Algerbra**

8x+7=6 (subtract the 7 from left side) 8x=-1 (divide the 8 on both sibes) x= (-1/8)
*March 24, 2013*

**physics**

YOU HAVE TO CHECK If Alice now applies QFT2n and measure, she will still get k with probability 99%. AND If she does as in the previous option, she will get k with probability 99%.
*March 22, 2013*

**math**

$8.00
*March 17, 2013*

**Math**

I think it should be x<=5/6 1. multiply thru by 5.... 2x-15x+10>=5x-5 2. combine like terms... -13x+10>=5x-5 3. get your variables on one side(-5x from both sides) -18x+10>= -5 4. isolate the variable... (-10..) -18x>=-15 5. /both sides by -18 !!careful!! ...
*March 17, 2013*

**hs geometry**

It's a proportion...53/63=x/67 in other words... st.height/st.shadow=tr.height/tr.shadow Solve by cross multiplying...63x=53*67 so x=56.37inches.. Good Luck!
*March 17, 2013*

**math**

64t^6 r^5g^3
*March 17, 2013*

**Physics**

Consider a pair of parallel plates with a potential difference of 12 V and are separated by 12 cm. What is the potential energy of a 1.0 C charge at point A, exactly 30. cm from each plate?
*March 16, 2013*

**math**

44c-4c^3
*March 16, 2013*

**Math**

Ms. Sue ???? i could have 0 toppings (that's 15).....or i could have 1 topping (x's 15 flavors) - that's 1215 ...or i could have 2 toppings 81x80(x's 15 flavors) that's 97200 more... Don't i have to get the sum of all of the combinations ??
*March 16, 2013*

**Math**

If I have 15 flavors of ice cream and 81 different toppings, how many different combinations could I create (assuming only 1 flavor of ice cream in the container at a time)? I got 36267774588438900000000000 ??? IS THIS RIGHT???
*March 16, 2013*

**Chemistry**

The specfic heat of iron is 0.11cal/g C. The heat of fusion of iron, the heat required to convert iron from a solid to liquid at its melting point, is 63.7cal/g. Iron melts at 1530 C. How much heat must be added to 2g of iron at 25c to completely melt it?
*March 15, 2013*

**Chemistry**

How many moles of gas are in a 30 liter scuba canister if the tempature of the canister is 300 k and pressure is 200 atmospheres?
*March 12, 2013*

**Chem**

I have a balloon that can hold 100 liters of air. If i blow up this balloon with 3 moles of oxygen gas at a pressure of 1 atmosphere, what is them tempature of the balloon?
*March 12, 2013*

**Chem**

How many moles of gas are in a 30 liter scuba canister if the tempature of the canister is 300 k and pressure is 200 atmospheres?
*March 12, 2013*

**Math**

I think you may have misread the question. Check to see if .005x^2 is actually -.005x^2. Then follow the directions above. When you graph the flight of an object it should be a parabola that opens downwards. Think of the graph as a side view of the rock where the x-axis is the...
*March 11, 2013*

**Math**

A rock band has 5 members, and 2/5 of the members play string instruments. Also, 0.4 of the members sing. Does the band have the same number of string instrument players as singers. I think no. Am i correct? Please explain it.
*March 6, 2013*

**Math**

I mean it
*March 6, 2013*

**Math**

Thank you
*March 6, 2013*

**Math**

What's 6/20 in simplest form? ( I know what simplest form is)
*March 6, 2013*

**Math**

the number can be divided by a greater sum then.
*March 6, 2013*

**Physics**

A pitcher throws a baseball with a horizontal velocity of 132 ft/s (90 mph) toward home plate that is approximately 60 ft. away. What is the vertical drop of the ball when it reaches the plate? g = 32 ft/s^2.
*February 26, 2013*

**Physics**

A long jumper leaves the ground with an initial velocity of 12 m/s at an angle of 28-degrees above the horizontal. Determine the time of flight, the horizontal distance, and the peak height of the long-jumper.
*February 26, 2013*

**Physics**

Train A starts at 4 miles South of a bridge and heads North at a constant speed of 30 miles per hour. Train B starts 6 miles North of the bridge. a. What velocity must Train B have so that the two trains cross the bridge at the same time? b. If Train B goes at 35 miles per ...
*February 26, 2013*

**Physics**

A train is moving towards a destroyed bridge. The velocity of the train remains constant at 20 m/s. A person inside the train realizes that they will die unless they run to the back of the train and jump out. If the person is 15 m from the back of the train and the back of the...
*February 26, 2013*

**Physics**

At a certain instant, a ball is thrown downward with a velocity of 8.0 m/s from a height of 40 m. At the same instant, another ball is thrown upward from ground level directly in line with the first ball with a velocity of 12 m/s. Find (a) the time when the balls collide and (...
*February 26, 2013*

**Physics**

A plane is flying at 25 degrees north of west at 190km/ h. Suddenly there is a wind from 15degrees north of east at 45 km/ hr. what is the planes new velocity with respect to ground in standard position
*February 22, 2013*

**Physics**

Plane flying southwest at 155mi/hr. their is a wind from the west at 45.0mi/hr. what's the planes new velocity
*February 21, 2013*

**MaTH**

so is the perpendicular line is -2/3? What is the parallel line?
*February 18, 2013*

**MaTH**

Consider the line 9x-6y=-3 . What is the slope of a line parallel to this line? What is the slope of a line perpendicular to this line?
*February 18, 2013*

**Mth**

I suck in math as you can see and yes I will love more help
*February 18, 2013*

**Math (Pre-Cal)**

There is exactly one triangle the length of whose sides are integers in arithmetic progression and whose area is 156 square units. Find the perimeter of this triangle.
*February 11, 2013*