Saturday

December 3, 2016
Total # Posts: 1,155

**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*

**bussiness math**

janusry

*May 23, 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 through 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*

**Math**

An airplane approaches a runway at a 3 degree angle of depresssion. If the plane is flying at 30,000 ft., find the ground distance from the airport to the point directly below the plane when the pilot begins the descent. Round your answer to the nearest foot.

*January 30, 2013*

**Math**

An airplane approaches a runway at a 3 degree angle of depresssion. If the plane is flying at 30,000 ft., find the ground distance from the airport to the point directly below the plane when the pilot begins the descent. Round your answer to the nearest foot.

*January 30, 2013*

**Biochemistry**

Do you add Nacl or HCL if your target buffer pH is 8, and the buffer is HEPES

*January 30, 2013*

**Physics**

Two forces are applied to a car in an effort to move it, as shown in the following figure, where F1 = 433 N and F2 = 354 N. (Assume up and to the right as positive directions.) F1 is 10 degrees west of the y axis, F2 is 30 degrees east of the y axis. (a)What is the direction &...

*January 30, 2013*

**Physics**

Forces of 11.3N north, 19.1N east, and 14.5N south are simultaneously applied to a 4.12kg mass as it rests on an air table. What is the magnitude of its acceleration? What is the direction of the acceleration in degrees? (Take east to be 0 degrees and counterclockwise to be ...

*January 26, 2013*

**Physics**

A rowboat crosses a river with a velocity of 3.30 mi/h at an angle 62.5° north of west relative to the water. The river is 0.795 mi wide and carries an eastward current of 1.25 mi/h. How far upstream is the boat when it reaches the opposite shore?

*January 25, 2013*

**MATH**

THREE QUARTERS OF A POUND OF HONEY COSTS $4 HOW MUCH HONEY WOULD YOU GET FOR $6

*January 23, 2013*

**Trigonometry**

cos 17pi/6 + tan 17pi/6

*January 23, 2013*

**Physics**

compare the collision of a baseball and bat with the collision of a baseball and a fielder's glove when the baseball is caught. During which collision is there a greater momentum change for the baseball?

*January 22, 2013*

**math**

what is 0.0678/100

*January 17, 2013*

**Physics**

Question: particle J with zero initial mass and X energy accelerates from a static start to 'C' (light speed) in a time frame of N and mass increases 10 to the 28th power per nanosecond- -What is the mass on particle J? -What is the energy of particle J?

*January 16, 2013*

**PLEASE HELP BIO**

If the side chain of a glutamic acid residue has a pKa of 4.1, at pH 6.1 the ratio of uncharged to charged side chain would be about A. 100:1 B. 10:1 C. 1:1 D. 1:10 E. 1:100 -i HAVE NO IDEA Which of the following amino acids has a side chain that can serve ONLY as a hydrogen ...

*January 16, 2013*

**biology**

If the side chain of a glutamic acid residue has a pKa of 4.1, at pH 6.1 the ratio of uncharged to charged side chain would be about A. 100:1 B. 10:1 C. 1:1 D. 1:10 E. 1:100

*January 16, 2013*

**biology**

Which of the following amino acids has the most hydrophilic side chain? A. F B. Q C. V D. M E. A

*January 16, 2013*

**biology**

Which of the following amino acids has a side chain that carries a negative charge in its conjugate base form? A. H B. W C. C D. K E. N

*January 16, 2013*

**physics**

The largest-caliber antiaircraft gun operated by the German air force during World War II was the 12.8 cm Flak 40. Suppose this weapon fired a 26.2 kg shell with a muzzle speed of 800 m/s. What propulsive force was necessary to attain the muzzle speed within the 6.00 m barrel...

*January 6, 2013*

**Physics**

Find the speed, v, of a pendulum at the bottom of its swing (B), given that it has mass m and initial height at A is h (the difference in height from B to A). Your answer will be in terms of g as well. Included is a drawing of a pendulum at its maximum height (A), and at its ...

*December 27, 2012*

**Linear Algebra**

Can you perform using matrix? Thank you very much

*December 18, 2012*

**Linear Algebra**

Consider the system x-2y=k-1 4x+(1-k^2)y=8 For what values of k does the system have a. unique solution? b. infinitely many solutions? c. no solution?

*December 18, 2012*

**math steve**

steve can you explain step by step please 8x=5y and 3y=14z then 12x= how many z's

*December 9, 2012*

**math**

if 8x=5y and 3y=14z then 12x= how many z's

*December 9, 2012*

**calculus**

A 100 inch piece of string is cut into 3 pieces. One piece forms a circle, one forms a square and 1 forms an equilateral triangle. If the perimeter of the triangle is equal in length to the perimeter of the square how long should each piece of string be to minimize the total ...

*November 19, 2012*

**math**

compare two cell phone companies and determine which is the better deal. Needs to be in a y=mx+b equation for each company. company a $40 base rate plus every minute costs .05 company b base rate $30 plus every minute costs .07 based on 800 minutes PLEASE HELP ME ASAP!

*November 18, 2012*