Word problem Definition and 493 Threads

This is not a homework question. It is a question my sister asked me, and although I could solve it, I could not explain some parts of the solution. The question is: John and Mary are working on a job together. If John does it alone, it will take him 7 days, while Mary can do it alone in...

Homework Statement A 240gram toy car is driven by an electric motor that has a constant power output. The car can climb a 24° incline at 16m/s and can travel on a horizontal table at 39m/s. The frictional force retarding the motion is kv, where k is a constant and v is its speed. How steep...

Homework Statement Let b(t) be the number of births in the United States at the end of year t, and let d(t) represent the number of deaths in the United States at the end of year t. If p(t) is the population of the United States at the beginning of year t, write a function c(t) that...

I have been trying to figure this problem out for more then 90 minutes and I think I'm past the point where I'm being productive: A population P satisfies the differential equation: P^'(t)=10^{-5}P(t)(15000-P(t)) For what value P(0) of the initial population is the initial growth rate P'(0)...

Homework Statement A 6-gallon radiator is filled with a 40% solution of antifreeze in water. How much of the solution must be drained and replaced with pure antifreeze to obtain a 65% solution? The answer is given: Ans. 2.5 gallons The Attempt at a Solution Let x be the amount of added...

The function s(t)=t2+tlnt gives the position from time [1,e] find: a. the velocity at time t b. the acceleration at time t c. describe the motion of the object: when is it moving forward or moving backward. also compute the total distance traveled during the interval d. when is the object...

a person with mass m stands at the outer edge of a round platform whose radius is r and whose mass is m2. the platform is rotating at a speed of ...rad/s. Assuming the platform to be a free rotating disk, what would be its angular speed if the person walked to its center? Then the answer book...

Homework Statement A Tsunami has been generated as a plane wave 4000km off the shore of California. The sea surface displacement is found to be 3 meters and the wavelength of the tsunami is 100km. You can assume a depth of 4000m from the location of wave generation to shore. a.) Calculate...

"Newton 2nd Law" word problem help Homework Statement When the click beetle jumps in the air, its acceleration upward can be as large as 400.0 times the acceleration due to gravity. (An acceleration this large would instantly kill any human being.) For a beetle whose mass is 40.00 mg...

Homework Statement a tall tree and a short tree of the same mass density and width are cut at the base at the same time. why does the small tree hit the ground first? Homework Equations none. its a word problem The Attempt at a Solution gravity id pushing in different ways?

Homework Statement suppose that a heavy person and a light person are balanced on a teeter totter made of plank wood. each person moves toward the fulcrum 25cm. why will the lighter persons end go down?? Homework Equations not needed The Attempt at a Solution something about forces...

momentum word problem... Problem: A tennis ball initially moves with a velocity of 30.0 m/s horizontally to the right. A tennis racket strikes the ball, giving it a velocity of 30.0 m/s to the left. Treat the collision as elastic and the ball and racket as particles of mass 0.0500= m1 kg...

I added two pictures.. One of the word problem and one of my diagram I made.. My work: 1.Wnet = Kf - Ki -Ugf = Kf... -mgy = mv^2/2 ... - gy = v^2/2 2. x^2 + y^2 = 1780^2 dy/dx = -x/y = velocity (v) at point (x,y) 3. gy = x^2/(2y^2) 4. gy = (1780^2 - y^2)/(2y^2) ...

Tarzan, who weighs 875 N, swings from a vine through the jungle. How much work is done by the tension in the vine as he drops through a vertical distance of 4.00 m? The answer is zero. Why is this?

Homework Statement A farmer can sell his crop for p= -t^2+60t+100 dollars per ton, where p is price and t is the number of days after Oct. 1st. Additionally, the farmer must sell his crop on or before Oct. 10 to pay his outstanding credit card bills. On what day should he sell to maximize...

Let p be a positive constant. Suppose that a random variable X has probability function f(x)=cxp(1-x) for 0≤x≤1. Find formulas for c, μx, and Var(X) in terms of p. I know Var(X)=∫(x-μx)2f(x)dx I know that I did not show any work so please just give me a hint (I'm not asking you to solve...

Homework Statement A) if http://www4d.wolframalpha.com/Calculate/MSP/MSP10819hf7feh5hf5hh7e00004ga728h1d42i6h0c?MSPStoreType=image/gif&s=18&w=161&h=20 Find the partial derivatives? B) Suppose you are manufacturing blackboards and whiteboards and that P is your monthly profit when your...

Homework Statement A company sells a certain product and determines that the best price that each item/product must be sold for is given by the formula P=1,620 Square Root X Over X. AKA P=1,620 Square Root X divided by X. X is the # of items sold. Each item cost's $40 to produce4. All items...

Homework Statement An object is moving to the right, and experiencing a net force that is directed to the right, The magnitude of the force is decreasing with time. the speed of the object is: constant or increasing?? Homework Equations none? The Attempt at a Solution constant??

Ok I know this isn't exactly a direct physics problem but I wasn't sure where to post this. Im writing up a lab report in word 2008 mac and whenever I insert an equation it pushes the text down a little and it sits above the text even though its all technically still the same line. Also the...

Homework Statement A quartic function has x-intercepts of -5, -1, 2, and 4. The point (3.-8) lies on the curve. Determine an equation of the function. Homework Equations The Attempt at a Solution y = k (x+5)(x+1)(x-2)(x-4) Expanded form: f(x)=kx^4 + 9x^2 - 38x + 40 <---My...

In this problem, assume researchers have constructed a risk score for HIV for the U.S. population, which is a function of risk factors such as frequency of unprotected sex, use of intravenous drugs, having another sexually trans- mitted infection, etc. Assume each risk factor measured is...

Homework Statement A rectangular shipping container that the Food Bank uses to store their tinned food, has a volume of 2500 cm3. The container is 4 times as wide as it is deep, and 5cm taller than it is wide. What are the dimensions of the container Homework Equations The...

Homework Statement 2 People build a sandcastle of 36cm by 48cm by 60cm. Later they learn that the box will be smaller; a certain amount will be taken off each of the length width and height Homework Equations The Attempt at a Solution a) write a p(x) > (36-x) (48-x) (60-x)...

Homework Statement Kaylas lemonade stand has experienced rises /falls in sales caused by temperature changes over 2 summers. Her sales over the first two weeks of summer were tracked according to the model S(x) = x^3 -12x^2 +36x, where x is the number of days and S(x) is the number of sales...

Homework Statement If the population y of rats on a farm at time t (in weeks) satisfies: dy/dt = -y(y-100)/50 then how many rats per week should be killed to eradicate the population? Homework Equations None known. The Attempt at a Solution The ODE dy/dt is autonomous, so I can...

I added a picture my work is inside the picture...

A snow-covered ski slope makes an angle of θslope = 29.0° with the horizontal. When a ski jumper plummets onto the hill, a parcel of splashed snow is thrown up to a maximum displacement of 1.70 m at θsnow = 19.0° from the vertical in the uphill direction as shown in the figure below. (a)...

In a game of American football, a quarterback takes the ball from the line of scrimmage, runs backward for 10.5 yards, and then runs sideways parallel to the line of scrimmage for 15.0 yards. At this point, he throws a forward pass 55.0 yards straight downfield perpendicular to the line of...

Homework Question: Four identical 4Ω resistors have been connected in such a way that their total resistance is 4Ω. Draw a diagram to show how they are connected. My Question: How do you solve a question like this? How do you classify it as a parallel or series circuit or does it even...

Homework Statement Homework Statement [/b] A hockey team plays in an arena with a seating capacity of 15,000 spectators. With the ticket prices set at $12, average attendance at a game has been 11,000. A market survey indicates that for each dollar the ticket price is lowered, average...

Homework Statement A cargo ship is tied up at the dock. At low tide, a 12-m long unloading ramp slopes down from the ship to the dock and makes an angle of 30 degrees to the horizontal. At high tide, the ship is closer to the dock, and the unloading ramp makes an angle of 45 degrees t othe...

Homework Statement Ok here is the problem: 100 loaves of bread are to be distributed such that the quantities form an arithmetric sequence, among 5 people. The first 2 together receive 1/7 of the remaining 3, together. How much (loaves and fractions) does each receive? Homework...

Homework Statement If an object is dropped from a height of 80m , its approximate height, h(t) metres above the ground t seconds after being dropped is given by the function h(t) = -5t^2 + 80 a) graph the functions b) find and graph the inverse c) is the inverse a function d) what does...

Homework Statement Sloping roof : The diagram shows a set of coordinate axes superimposed on the cross section of a sloping roof of height h metres and width w metres. The equation of one half of the cross section is y=-0.7x + 1.9 a) What is the equation of the other half of the...

Help with an investment matrix word problem! Can anyone give me the 3 equations in general form that I need to solve this matrix? A person will put 30% of his investment into a stock fund that earns a 9% annual rate of return. He will put 20% in precious metals currently growing at 40% and...

Hi all. I'm a nurse in the middle of a nightmare math class. It is second half of college algebra but it may as well be Greek. The professor is a PhD in engineering and is teaching way over my head- and others from what I hear. I have never failed a class in my life but this may be a first...

The word problem: If the product of a number and -5 is reduced by 2, the result is 26 less than twice the opposite of the number. What is the number? I wrote it out like this: n x (-5) - 2 = 2(-n) - 26 I'm really at a loss here. Normally when there's a variable, my teacher says to get the...

1. Find the dimensions of the rectangle with the largest area that can be inscribed in the upper semi-circle given by x^2+y^2 ≤ 16, y≥0. 2. I thought I'd use A=lw 3. This is but a guess..so take it with a grain of salt.. height=2x base= x^2+y^2 A(x) = 2x(x^2+y^2) = 2x^3+2xy^2 A'(x) =...

Two amateur meteorologist, living 4km apart (4000m), see a storm approaching. The one farthest from the storm hears a loud clap of thunder 9 sec after the one nearest. Assuming the speed of sound is 340m/sec, determine an equation that models possible locations for the storm at that time...

niagra falls skywheel, a ferris wheel has a diameter of 50.5 m and rotates 1 revolution in 2 minutes. the lowest point on the wheel is 2.5 m from the ground. This is the equation i have come up with, please tell me if this is right or not, and if it is not please come up with your own...

Homework Statement A 10.000g sample of toothpaste containing stannous fluoride gives a 0.145g precipitate of stannous phosphate. What is the percentage of SnF_2 in the toothpaste sample?Homework Equations (Actual yield)/(Theoretical yield) * 100% 3SnF_{2}_{(aq)} + 2K_{3}PO_{4}_{(aq)}...

Amanda, Bryce, and Corey enter a race in which they have to run, swim, and cycle over a marked course. Their average speeds are given in the table. Corey finishes first with a total time of 1 hours 45minutes, Amanda comes in second with a time of 2 hours 30 minutes, and Bryce finishes last with...

The problem: "A commercial customer orders 81 gallons of paint that contains equal amounts of red paint, green paint, and blue paint - and hence, could be prepared by mixing 27 gallons of each. However, the store wishes to prepare this order by mixing three types of paint that are already...

Homework Statement Six Identical pipes, each with radius of 1 foot are ties tightly together with a metal band... Find the length of the metal band... I posted a picture... My strategy is dividing the figure in half Then finding the measure of the two arcs in red ( which should be...

Homework Statement If a pipe is between two blocks... one block being 1 inch tall and the other block being 2 inches tall. Between the two blocks is an arc that is 6 inches... What is the radius? Can some one please help me... I have no Idea what to do.. thank you.

A new technology is introduced into a community of 5000 individuals. If the rate dN/dx at which the technology spreads through the community is JOINTLY PROPORTIONAL to the number of people who use the technology AND the number of people who do not use it, (1)WRITE A DIFFERENTIAL EQUATION FOR...

Homework Statement A 1.8 m tall student is trying to escape from the minimum security prison in Tono. She runs in a straight line towards the prison wall at a speed of 4.0 m/s. The guards shine a spotlight on the prisoner as she begins to run. The spotlight is located on the ground 30 m...

Homework Statement A jet flew from Tokyo to Bangkok, a distance of 4800 km. On the return trip, the speed was decreased by 200km/h. If the difference in the times of the flights was 2 hours, what was the jet's speed from Bangkok to Tokyo? Homework Equations Distance=(speed)(time)...

Homework Statement A tank with a rectangular base and rectangular sides is to be open at the top. It is to be constructed so that its width is 4 meters and its volume is 36 cubic meters. If building the tank covers $10 per square meter for the base and $5 per square meter for the sides, what...