Tuesday

October 25, 2016
Total # Posts: 1,935

**Math**

How long will it take for a 1 g sample of Polonium 210 to lose all but 1/28 of its radioactivity if the half-life is 140 d?

*August 1, 2011*

**Math**

In a recent dig, a human skeleton was unearthed. It was later found that the amount of 14C in it had decayed to (1/rt8) of its original amount. If 14C has a half life of 5760 years,how old was the skeleton?

*August 1, 2011*

**Math**

In 1976 a research hospital bought half a gram of radium for cancer research. Assuming the hospital is still exists, how much of this radium will the hospital have in the year 6836 if the half-life of radium is 1620 years?

*August 1, 2011*

**Math**

In 1976 a research hospital bought half a gram of radium for cancer research. Assuming the hospital is still exists, how much of this radium will the hospital have in the year 6836 if the half-life of radium is 1620 years?

*July 31, 2011*

**Math**

y=-x^2+1.5x+2 Find the maximum value.

*July 31, 2011*

**Math**

What are some examples of exponential function (Using the formula: Al = A0(1/2)^t/h ), trig functions that are used to find amplitude, period, max, min etc., and combinations of transformation at home or in life in general?

*July 30, 2011*

**Math**

Use the information provided to write the vertex form equation of each parabola. a)y + 60x + 294 = -3x^2 b)−(y+1) = (x−4)^2

*July 27, 2011*

**Math**

A piece of cardboard has a length of 60cm and a width of 40cm. In order to make the cardboard into an open box, a box with no lid), a piece of length x must be cut out of each corner. Write an equation to represent each dimension of the box.

*July 26, 2011*

**Math**

Simplify: (3x+5)^3-3x(x^2-1)

*July 26, 2011*

**Math**

If f(x)=5x+2 and g(x)=x^2+3, then what is f(g(x))?

*July 25, 2011*

**Math**

Which of the following is a solution to the trigonometric equation 2cos2 x - 5cos x + 2 = 0? A) 240 degrees B) 135 degrees C) 270 degrees D) 90 degrees

*July 23, 2011*

**Math**

Identify the period in degrees and radians: y = sin2x: y = cos(3/2)x: y = 2sin(1/2)x: y = 1.5cos0.25x:

*July 23, 2011*

**Math**

Given that the formula is y=-9cos12x+9 What is k in radian?

*July 22, 2011*

**Math**

Time Height above ground 0 45 3 65 6 80 9 85 12 80 15 65 18 45 21 25 24 10 27 5 30 10 33 25 36 45 I know the following things: The minimum is 5 while the maximum is 85. amplitude: 85-5/2 = 40 period =360/45 = 8 vertical translation = 5 + 40 = 45 But I can't seem to get the...

*July 22, 2011*

**Math-please help!!**

Make a word document with the key points (in tables/charts) for the following functions, given in the form y=asink(x+d)+c Start with multiplication/division (multiply ‘y’ by a, divide ‘x’ by k) Then add c to the y values, subtract d from the x values 1.y=...

*July 19, 2011*

**Math**

1) Find three functions with unlimited domains and ranges. 2) Find two functions with restricted domains. 3) Find two functions with restricted ranges. Im confused as to how I can find the answer for these question, can you please explain along the steps.

*July 19, 2011*

**Math**

A ski resort is installing tows on its new ski runs. The baby hill has a vertical height of 500.0 m and is inclined at 42o. Determine the appropriate length of the T-bar cable if it goes to the top of the hill and returns.

*July 19, 2011*

**Math**

A football player is attempting a field goal. The angle formed by the player's position on the field and the line of sight to each upright is 33o. If the distances to the uprights are 7.5 m and 10.0 m, calculate the width of the uprights.

*July 19, 2011*

**Math**

Prove each identity: a) 1-cos^2x=tan^2xcos^2x b) cos^2x + 2sin^2x-1 = sin^2x I also tried a question on my own: tan^2x = (1 – cos^2x)/cos^2x R.S.= sin^2x/cos^2x I know that the Pythagorean for that is sin^2x + cos^2x That's all I could do.

*July 18, 2011*

**Math**

Prove each of the following identities. a)tan^2x = 1 – cos^2x/cos^2x b)sinx/1 – sin^2x = tanx/cosx

*July 17, 2011*

**Math**

Solve for all possible values of x where O°≤x360°. sin x=2/3.

*July 17, 2011*

**Math**

Solve for all possible values of x where O°≤x360°. sin x=2/3. I do not understand these types of questions please answer in as much detail as you can so I can do them myself.

*July 17, 2011*

**Math**

Solve for all possible values of x where O°≤x≤360°. tan x = -1/√3 cos x = 1/2

*July 17, 2011*

**Math**

Determine the EXACT values of each of the following: a) sin 240° b) cos 135°

*July 17, 2011*

**Math**

Find the angle (Θ) for a terminal arm with the following coordinates(round to one decimal place): (5,8)

*July 16, 2011*

**Math**

What are some examples of acute and obtuse triangles in a home?

*July 16, 2011*

**Math**

Determine the exact value of: sin30° + cos225° + sin150° + cos330°

*July 15, 2011*

**Math**

The winner of a popular lottery is offered one of two options: i) a lump sum of $102 500 ii) $1000 every month for 10 years If the money can be invested at 3.0% p/a, compounded monthly, which option should the winner choose? Justify your reasoning. Every three months, Carlos ...

*July 14, 2011*

**Math**

How much would you have to invest at 6.3% interest for it to have grown to $67.06 in five years

*July 14, 2011*

**Math**

That can't be right...the correct answer shows it should be 12 years.

*July 13, 2011*

**Math**

You invest $25 in an account earning 7.5% interest per year. After how many years is it worth $42.50?

*July 13, 2011*

**Math**

Sam gets deposits a total of $3500 every three months to the bank which earns a 6.5% p/a. After five years how much will he have in his account? Ren wants to buy a new car that costs $26255, so, he would deposit money into his savings account with an interest rate of 3.9% p/a ...

*July 13, 2011*

**Math**

Stacey buys a $1000 RRSP today. After one year she adds $2500. By the end of the second year, the money has grown to $3851 as it has earned interest over time. What rate of interest does the money earn? 1000x^2 + 2500x - 3851 Use the quadratic formula above and your calculator...

*July 12, 2011*

**Math**

Determine the present value of the annuity: $1500 at the end of each 3-month period, for 5 years, at 4.5% p/a, compounded quarterly

*July 12, 2011*

**Math**

Imagine you have invested $500 in an account that pays 5% simple interest per year. Can you find an arithmetic sequence to look for the amount of money in the account after 20 years?

*July 12, 2011*

**Physics**

If you go to google and type "conservation of momentum photogate lab penn state" this is just like the experiment we performed. It should be the top result "Physics 250 Laboratory: Conservation of Momentum. Hope this helps.

*July 11, 2011*

**Physics**

So I had an exam today and one of the questions is bugging me. Our professor is out of town for a few days, so we had a proctor and I still can't figure it out using my notes. It was a question about two carts and deals with momentum. Cart A is at rest between two ...

*July 11, 2011*

**Physics**

So I had an exam today and one of the questions is bugging me. Our professor is out of town for a few days, so we had a proctor and I still can't figure it out using my notes. It was a question about two carts and deals with momentum. Cart A is at rest between two ...

*July 11, 2011*

**Math**

tn - tn-1 = 2n + 3; t1 = 10 Find the first five terms in the sequence using this recursive formuls

*July 11, 2011*

**Math**

tn - tn-1 = 2n + 3 Find the first five terms in the sequence using this recursive formuls

*July 11, 2011*

**chemistry**

How many grams of acetic acid (MW = 60 g/mol, pKa=4.75) are needed to change 1000 L of water with a pH of 11 to a pH of 5.5?

*July 8, 2011*

**MATH**

Halley's comet appears in the sky approximately once every 77 years. If the comet was seen in by Astronomer Edmund Halley in 1531. How many times has the comet been spotted since?

*July 8, 2011*

**chemistry**

How many grams of HCl are needed to change 1000 L of water with a pH of 11 to a pH of 5.5?

*July 8, 2011*

**PHYSICS **

A 240 g block on a 41 cm-long string swings in a circle on a horizontal, frictionless table at 73 rpm. (a) What is the speed of the block? (b) What is the tension in the string?

*July 7, 2011*

**physics**

A 5.0 m diameter merry-go-round is initially turning with a 4.6 s period. What is the speed of a child on the rim?

*July 7, 2011*

**Math(Pre=Calc)**

The first term in a sequence of number is t1 = 4. The terms that follow are defined by the formula: tn - tn-1 = 3n -2. Determine the value of t50.

*July 6, 2011*

**physics**

A penguin sliding on ice has an initial velocity of 5 m/s due north. Due to a strong wind, the penguin has an acceleration of 2 m/s2 SE. What is the penguin’s displacement (magnitude and direction) after 4 seconds

*July 5, 2011*

**physics**

Three forces act on a 3 kg box: 10 N South-west, 17 N North-west, 5 N due East. What is the acceleration of the box?

*July 5, 2011*

**physics**

You throw a ball downwards with a speed of 10 m/s. It hits the ground 4 meters below from where you threw it. How long is the ball in the air and what is the ball’s velocity just before it hits?

*July 5, 2011*

**physics**

A .5 m long, 3 cm diameter metal bar has a Young’s Modulus of 7.0x1010 N/m2. If a 50,000 N force is applied to the end of the bar, by how much will it compress?

*July 5, 2011*

**speech **

it has to be one describing word but i need two more and those websites were no help to me

*July 3, 2011*

**Algebra 2**

what number did they give you because you have to plug the answer in for X these are two differnt parts. The question is say use X+5 if x is greater than 0 or the answer is three if x is less than 0

*July 3, 2011*

**physics**

A 3.0 m tall, 42 cm diameter concrete column supports a 230,000 kg load. By how much is the column compressed? Assume Young's modulus for concrete to be 3.0 1010 N/m2. in mm

*July 2, 2011*

**PHYSICS**

a 10cm long spring is attached to the ceiling. when a 2.6kg mass is hung from it, the spring stretched to a length of 15cm. what is the spring constant k how long is the spring when a 4.0 kg mass is suspended from it

*June 30, 2011*

**physics**

a skater holds her arms outstretched as she spins at 140 rpm. What is the speed of her hands if they are 125 cm apart?

*June 28, 2011*

**Physics**

A 36 kg box hangs from a rope. What is the tension in the rope if the following are true? (a) The box moves up a steady 5.0 m/s? (b) The box has vy = 5.0 m/s and is slowing down up at 5.0 m/s2?

*June 22, 2011*

**physics**

thank you!

*June 22, 2011*

**physics**

A 20 kg crate is placed on a horizontal conveyor belt. The materials are such that μs = 0.6 and μk = 0.3. (c) What is the maximum acceleration the belt can have without the crate slipping? (d) If acceleration of the belt exceeds the value determined in part (c), what...

*June 22, 2011*

**physics**

How much force does an 60 kg astronaut exert on his chair while accelerating straight up at 8m/s squared?

*June 21, 2011*

**physics**

How much force does an 60 kg astronaut exert on his chair while accelerating straight up at 8m/s squared?

*June 21, 2011*

**PHYSICS**

A 900 kg car pushes a 1900 kg truck that has a dead battery. When the driver steps on the accelerator, the drive wheels of the car push against the ground with a force of 4800 N. (a) What is the magnitude of the force of the car on the truck? (b) What is the magnitude of the ...

*June 21, 2011*

**PHYSICS**

Zach, whose mass is 67 kg, is in an elevator descending at 12 m/s. The elevator takes 3.5 s to brake to a stop at the first floor. (a) What is Zach's apparent weight before the elevator starts braking? (b) What is Zach's apparent weight while the elevator is braking?

*June 19, 2011*

**physics**

King Arthur's knights fire a cannon from the top of the castle wall. The cannonball is fired at a speed of 54 m/s and at an angle of 34°. A cannonball that was accidentally dropped hits the moat below in 1.1 s.(a) (a)How far from the castle wall does the cannonball hit...

*June 19, 2011*

**physics**

A supply plane needs to drop a package of food to scientists working on a glacier in Greenland. The plane flies 92 m above the glacier at a speed of 135 m/s. How far short of the target should it drop the package?

*June 19, 2011*

**physics**

A go-cart has an initial speed of 23.4 m/sec. Fifteen seconds later the go-cart has a final speed of 36.8 m/sec. What is the magnitude of the go-cart's displacement?

*June 11, 2011*

**algebra**

How do I write this number in scientific notation 1. 8.68x10^1 2.1,900,000

*June 10, 2011*

**Physics **

A bullet with mass 4.91 g is fired horizontally into a 1.981-kg block attached to a horizontal spring. The spring has a constant 6.25 102 N/m and reaches a maximum compression of 6.38 cm. a) find the initial speed of the bullet-block system. b) find the speed of the bullet

*June 1, 2011*

**Pre-Calc**

1. Square both sides. (x+5)^5=(x+5) 2. FOIL the left side. x^2+10x+25=x+5 3. Subtract x and 5 from both sides. x^2+9x+20=0 4. Factor. (x+5)(x+4)=0 5. Solve using the zero product property. x+5=0 x+4=0 x=-5 and x=-4

*June 1, 2011*

**grammar**

Is this sentence. Mr. and Mrs. Lopez's plane tickets, incidentally were found in the lobby. Is this correct punctuation?

*May 29, 2011*

**finance**

47,912

*May 26, 2011*

**Algebra**

I could use some help on this please. Write a linear function that satisfies the given conditions: h(-1) = 4, h(0) = -5 Thanks!!!

*May 22, 2011*

**Physics**

In a physics lab experiment, a spring clamped to the table shoots a 18 g ball horizontally. When the spring is compressed 20 cm, the ball travels horizontally 4.9 m and lands on the floor 1.3 m below the point at which it left the spring. What is the spring constant?

*May 17, 2011*

**statistics**

The following data lists the average monthly snowfall for January in 15 cities around the US: 37 33 35 27 9 45 22 8 42 48 37 39 9 15 12 Find the mean, variance, and standard deviation

*May 15, 2011*

**calculus**

the derivative of f(x) = e^(sin x)cos(x)

*May 4, 2011*

**calculus**

f(x) = e^(sin(x))cos(x)

*May 4, 2011*

**calculus**

f(x) = e^(sin(x))cos(x)

*May 4, 2011*

**calculus**

i missed something in it sorry. it was ∫sec 2x tan 2x dx

*May 4, 2011*

**calculus**

its sec 2x

*May 4, 2011*

**calculus**

i don't get what you mean?

*May 4, 2011*

**calculus**

∫sec 2x tan x dx

*May 4, 2011*

**freshman chem**

if 5.00 g of ethanol is added to 15.0g of whater, what is the % concentration of ethanol in water??

*May 4, 2011*

**chemistry**

if 5.00g of ethanol is added to 15.0g of water, what is the % concentration of ethanol in water? THANKYOU

*May 4, 2011*

**English - Macbeth**

Think about Macbeth’s position at the conclusion of Act III. In what ways has his ambition, which allowed him to obtain the Scottish throne in the first place, begun to be detrimental to him? Cite specific examples from the play in your response. What does this question ...

*April 28, 2011*

**math**

16-4+1 = 13 13 to the 2nd power = 13 *13 13 * 13 = 169

*April 27, 2011*

**English**

I just finished reading Macbeth for school. My teacher assigned a essay for us to do. She asked if we think the witches' predictions were right or if the witches' predictions were disappointing because of duality and doublespeak. I said that I believe in neither and I ...

*April 27, 2011*

**math**

the answer ie 30

*April 26, 2011*

**Math**

$307,$330,$440,$405 (range

*April 24, 2011*

**chemistry**

A 1.00-L sample of dry air at 25 °C contains 0.0319 mol N2, 0.00856 mol O2, ... The main components of dry air, by volume, are N2, 78.08%; O2, 20.95%; Ar, ... by volume, of the following main gaseous components: N2, 74.1%; O2, ... What is the partial pressure of each gas ...

*April 19, 2011*

**allied health part 2**

I go to a medical high school, so this isn't to unfamiliar, but aren't C and D both medical care operations? I'm leaning towards D....

*April 13, 2011*

**Physiology**

The BP cuff constricts arteries and veins, so when the blood pulses to try and get through, that's what you'd hear. (The pounding) If that makes sense....?

*April 13, 2011*

**Chemistry**

Calculate the amount of heat required to raise the temperature of a 33 g sample of water from 6 Celsius to 24 Celsius.

*April 13, 2011*

**stereotypes in psychology**

Sorry. But who generally fit these based off of beliefs.

*April 11, 2011*

**stereotypes in psychology**

are good dancers. drive Hummers. have more fun. are great lovers. cause trouble. are ditzy. are on welfare. live off other people. have hot tempers. are good with money. drink a lot. eat a lot.

*April 11, 2011*

**statistics**

Among 17 metal parts produced in a machine shop, 6 are defective. If a random sample of four of these metal parts is selected, find: (a) The probability that this sample will contain at least three defectives. (Do not round the intermediate answers. Round your answer to 4 ...

*April 8, 2011*

**Logarithms**

Solve for x: {{{ln(x)+x=5}}}

*April 8, 2011*

**calculus**

determine the dimensions of a rectangular solid (with a square base) with maximum volume if it's surface area is 289 meters

*April 7, 2011*

**World history**

Try and do your own homework instead of posting the whole worksheet onto here

*April 6, 2011*

**Geometry**

Solve for x: 2 to x+1=x+2 to 3 or 2 to x+3= x+2 to x+5 (the proportions end up being the same in the end) I keep getting to the part after you FOIL, and then I get stuck

*April 5, 2011*

**math**

Well, when you know how many hours, you multiple that by 2 (for both days he will work), and then the answer to that by his salary of a whopping $750.

*April 4, 2011*

**math**

I agree. He surely doesn't work 24 hours a day for 2 days straight with a $750 salary? Come to think of it, I might if I made that much an hour!

*April 4, 2011*