Tuesday

February 9, 2016
Total # Posts: 4,666

**physics**

A diffraction grating with 150 slits per centimeter is used to measure the wavelengths emitted by hydrogen gas. At what angles in the fourth-order spectrum would you expect to find the two violet lines of wavelength 434 nm and of wavelength 410 nm? (angles in radians)
*December 12, 2014*

**Chemistry**

A gas occupies 21.0 L at 2.00 atm pressure and 27oC. Calculate its volume at STP.
*December 12, 2014*

**physics**

A stunt man 60kg jumps down straight down at bozs below 10m from a balcony and he's going down at a speed of 50km/h. What is the force exerted on the boxs?
*December 10, 2014*

**college gen chem**

An igneous rock contains a Pb−206/U−238 mass ratio of 0.367. How old is the rock? (U−238 decays into Pb−206 with a half-life of 4.50×109 yr.) I'm not sure how to get started on this :/
*December 6, 2014*

**Math**

What is the product in scientific notation? (1.4x10^3)(2.5x10^-6) Please answer and explain how you got the answer.
*December 6, 2014*

**physics**

According to the manual of a certain car, a maximum torque of magnitude 76.0 N · m should be applied when tightening the lug nuts on the vehicle. If you use a wrench of length 0.276 m and you apply the force at the end of the wrench at an angle of 75.00° with ...
*December 4, 2014*

**Math**

A fishing boat leaves port at 5 miles per hour at a bearing of 350∘ for 2 hours, then turns to a bearing of 40∘ at 12 miles per hour for 2 hours, and finally changes to a bearing of 180∘ at 10 miles per hour for 5 hours. At this point, the boat heads directly...
*December 3, 2014*

**stats**

so i found the equation SE = sigma/sqrt(n) I plugged in 1.5 for SE and 5 for sigma. i got n= 11.1 but that is not the correct answer..
*December 3, 2014*

**stats**

A normal population has mean 100 and variance 25. How large must the random sample be if we want the standard error of the sample average to be 1.5? I know the answer is 12. Would someone please be able to explain! and share what formula they used
*December 3, 2014*

**Math**

A fishing boat leaves port at 5 miles per hour at a bearing of 350∘ for 2 hours, then turns to a bearing of 40∘ at 12 miles per hour for 2 hours, and finally changes to a bearing of 180∘ at 10 miles per hour for 5 hours. At this point, the boat heads directly...
*December 3, 2014*

**Math**

A fishing boat leaves port at 5 miles per hour at a bearing of 350∘ for 2 hours, then turns to a bearing of 40∘ at 12 miles per hour for 2 hours, and finally changes to a bearing of 180∘ at 10 miles per hour for 5 hours. At this point, the boat heads directly...
*December 3, 2014*

**science**

You are not aloud to use outside help when doing a test.
*December 2, 2014*

**algebra**

if your base is 7 than x is 7^1/2, the square root of 7
*December 1, 2014*

**Calculus**

thank you
*December 1, 2014*

**Calculus**

I'm getting that r is the square root of 12, so dh/dt is 1/6pi ?
*December 1, 2014*

**Calculus**

Water is being poured into a spherical bowl of radius 4cm at a rate of 2cm3/s. How fast is the water level rising when it is at 2cm?
*December 1, 2014*

**Honors Pre- AlgebraMath**

5.9(13/14)+x(1/14)=5.8 and solve for x
*December 1, 2014*

**check my science hw please.**

If its not a town, I guess it is bigger. So, it should be D.
*November 30, 2014*

**check my science hw please.**

31. Which of the following is an example of a global environmental choice? A. a student deciding to ride a bicycle to school B. a family deciding to recycle their newspapers C. a town meeting about a new nature refuge. D. nations meeting to discuss the ozone layer. I got C as ...
*November 30, 2014*

**check my science hw please.**

30. Laws can help endangered species by prohibiting A. Captive breeding B.habitat preservation C diversity of genes D. products made from the species I got D, I have a feeling that this may be wrong.
*November 30, 2014*

**check my science hw please.**

26. In the last few centuries, the number of species becoming extinct on Earth has A.decreased dramatically B. decreased slightly. C. increased slightly. D.increased dramatically I think it should be C.
*November 30, 2014*

**check my science hw please.**

It just said "areas" on my choice
*November 30, 2014*

**check my science hw please.**

25. All of the following factors affect an area's biodiversity EXCEPT A. areas B.number of endangered species C. climate D. diversity of niches. I got C for my answer.
*November 30, 2014*

**check my science hw please.**

wait, I had B for my answer, not A
*November 30, 2014*

**check my science hw please.**

24. can provide an economic benefit to A. drug companies B. tourists C.hikers D.endangered species I got A for my answer.
*November 30, 2014*

**check my science hw please.**

Is the answer C?
*November 30, 2014*

**check my science hw please.**

18. Which of the following would be a cost of drilling for oil in Antarctica? A. The supply of heating fuel would be increased. B.There would be a greater opportunity to study wildlife there. C. An oil spill could harm food sources for penguins. D. Many new jobs would be ...
*November 30, 2014*

**science**

10. One group of gases that is responsible for destroying ozone in the ozone layer is A.car exhaust fumes B.CFCs C.nitrogen oxides and sulfur oxides D. Carbon monoxide and carbon dioxide I got B for my answer.
*November 30, 2014*

**Physics**

A 50 kg cart rests on frictionless surface. A net force of 75 N acts on the carts over a distance of 2m. What maximum speed does the cart reach? Work: I can figure that the acceleration is 1.5m/s/s, Vi= 0. I was thinking maybe if I found time through the kinematic equation d=...
*November 30, 2014*

**ALGEBRA 2**

In triangle ABC , angle C is a right angle. Find the remaining sides and angles. Round your answers to the nearest tenth. Show your work
*November 28, 2014*

**Algebra math Question**

1574.0
*November 24, 2014*

**physics**

Question: Object A is moving at a maximum speed of 6m/s towards Object B. At 50 m away Object B accelerates from the approaching Object A at 0.3m/s^2. Does Object A catch up to Object B and if yes when? I don't know how to answer this at all or even which kinematic ...
*November 24, 2014*

**data**

I am looking for the school report each year regarding school violence and vandalism? I can not find this information on the internet, can you help me? Missouri school report.
*November 24, 2014*

**Health And Physical Ed**

your answers are correct I checked them.
*November 23, 2014*

**chem**

What are the expected charges on the following transition metals? Mn= Rh=
*November 23, 2014*

**College English**

can you write a essay map sentence from this sentence Christmas shopping shows that the law of the jungle is still with us.
*November 23, 2014*

**culture**

What culture would someone have if they live in Missouri
*November 22, 2014*

**Chemistry**

I dont understand where you are getting 6.022E23 from
*November 21, 2014*

**Chemistry **

A sample of sodium sulfate, Li2SO4, contains 6.78 x 10^23 formula units. How many moles of Li2SO4 are there in the sample? How many moles of Li+ ions are there in the sample?
*November 21, 2014*

**college chem**

Calculate the molar enthalpy of reaction standard enthalpy of formation below. H20 = -285.8 kj/mole H+ = 0.0 kj/mole OH- = -229.9 kj/mol H+(aq) + OH-(aq)→H2O(l) For this, don't you do the summation of products x stoichemtry + the sum of reactants x stoich. from there...
*November 20, 2014*

**College Chem**

How would temperature changes observed using a calorimeter differ for exothermic and endothermic reactions?
*November 20, 2014*

**college chem**

A student constructs a galvanic cell that has a strip of iron metal immersed in a solution of 0.1M Fe(NO3)2 as one half-cell and a strip of zinc metal immersed in a solution of 0.1M Zn(NO3)2 as the other half-cell. The measured cell potential is less than zero when the ...
*November 19, 2014*

**physics**

Determine the quantity of heat required to convert 1kg of ice at −20 degrees Celsius to water at 100 degrees Celsius? Specific heat capacities of water and ice water are 2302 J/kgK and 4186 J/kgK respectively
*November 19, 2014*

**Chemistry, HELP!**

1) If a soil had a pH of 5.5, how many milli-equivalents of acids would it have per 100 grams? 2) How many milli-equivalents of Ca need to be added to increase the pH of the soil to 6.8?
*November 18, 2014*

**physics**

In an experiment to verify Newton's law of cooling, the temperature of hot water in a calorimeter T/oC is plotted against time t/min. Which of the following is true about the graph? a. the graph is linear and parallel to the T-axis b. the slope of the graph is positive c. ...
*November 18, 2014*

**physics**

An air puck of mass 0.278 kg is tied to a string and allowed to revolve in a circle of radius 1.25 m on a horizontal, frictionless table. The other end of the string passes through a hole in the center of the table and a mass of 0.45 kg is tied to it. The suspended mass ...
*November 16, 2014*

**Calc**

evaluate the integral of 2e^xdx from -5 to 5.
*November 16, 2014*

**English**

Oh, okay. So A and D cannot be it. C would be my next choice, based on the quote.
*November 14, 2014*

**English**

Thoreau included the following sentence in Walden: "There is some of the same fitness in a man's building his own house that there is in a bird's building its own nest." Which of the following statements rephrases his literal comparison as a metaphor? A. A ...
*November 14, 2014*

**Math**

Which term best describes the solution of the situation represented by the system of inequalities? (Assume that x >= 0 and y >= 0.) 3x + 4y <= 8 2x + 4y <= 6 Answer choices given are: a. alternate optimal solutions b. one optimal solution c. unbounded d. infeasible...
*November 14, 2014*

**stats**

Weights of parts are normally distributed with varianceσ2. measurement error is normally distributedwith mean zero and variance 0.5σ2, independent ofthe part weights, and adds to the part weight. Upper andlower specifications are centered at 3σ about the ...
*November 14, 2014*

**Physics**

A block is placed on a frictionless ramp at a height of 14.5 m above the ground. Starting from rest, the block slides down the ramp. At the bottom of the ramp, the block slides onto a frictionless horizontal track without slowing down.At the end of the horizontal track, the ...
*November 13, 2014*

**Engineering**

A plane element is subjected to a shear stress τ = 360MPa which results to a shear strain σ = 0.008rad. a) determine the shear modulus G of the element b)What is the horizontal displacement, d, of the element if te height of the element is equal to 50mm I worked out ...
*November 11, 2014*

**Math**

Help meits due tomorrow
*November 9, 2014*

**Math**

Brandon buys a radio for 43.99$ in a state where the sales tax is 7% How much did he pay in taxes ? What is the total Brandon pays for the radio?
*November 9, 2014*

**math count warm up**

What positive four-digit integer has its thousands and hundreds digits add up to the tens digit. Its hundreds and tens digits add up to its once digit and its tens and ones digits add up to the two digit number formed by the thousands and hundreds digits? Answer is 1459 wanted...
*November 9, 2014*

**physics **

In a Little League baseball game, the 145 g ball enters the strike zone with a speed of 13.0 m/s. The batter hits the ball, and it leaves his bat with a speed of 21.0 m/s in exactly the opposite direction. 1. what is the magnitude of the impulse delivered by the bat to the ...
*November 5, 2014*

**physics **

An ice hockey puck slides along the ice at 15 m/s . A hockey stick delivers an impulse of 4.8kg/m/s causing the puck to move off in the opposite direction with the same speed. what is the mass of the puck?
*November 5, 2014*

**math**

thanks so much! can you help me understand this one as well? I have the integral from 0 to 2-2x of integrate (2-2x-y)dy... I thought you just take the integral with respect to y so it would be -y^2/2? (plugging the bounds it that would be -(2-2x)^2/2 but it comes out to be (2-...
*November 4, 2014*

**math**

integral of y^3/(y^4 +1) dy I don't get how you get (1/4) ln(y^4 +1) out of this. I thought you would do the quotient rule. but is that the same for integrals as it is the derivatice? help!
*November 4, 2014*

**sociology**

Mattie is a new sociology professor at the local college. During her first lecture, she noticed that some students were yawning. Based on her interpretation of the students yawning, Mattie has decided she is a boring teacher. This is an example of the process referred to as ...
*October 31, 2014*

**stats**

In the transmission of digital information, the probability that a bit has high, moderate, and low distortion is 0.01, 0.04, and 0.95, respectively. Suppose that three bits are transmitted and that the amount of distortion of each bit is assumed to be independent. Let X and Y ...
*October 31, 2014*

**Health**

Shut up, she's great! :) unlike you, idiot
*October 29, 2014*

**Physics**

A ball player hits a home run, and the baseball just clears a wall 20.3 m high located 119.0 m from home plate. The ball is hit an an angle of 35° to the horizontal, and air resistance is negligible. Assume the ball is hit at a height of 1.0 m above the ground. (a) What is...
*October 23, 2014*

**math**

how would you calculate teh largest prime number given a number x so for example say someone inputs 8 , the largest prime number is 7.
*October 23, 2014*

**Calculus**

I need help determining the intervals of increase, decrease and the intervals of upward and downward concavity given f prime. f'(x)=(64x^4 - 125x) ^(-2/3). Im not sure how to solve this. I know that the function has no intervals of decrease, its the rest im having trouble ...
*October 23, 2014*

**Teacherd aide**

Thank you very much Ms. Sue! (:
*October 20, 2014*

**Teacherd aide**

3. Which of the following techniques to arouse curiosity would work best with junior high students? A. Set up a curiosity corner. B. Use a "feelie" box. C. Use a teaser to introduce the topic. D. Set up a discovery learning center. I ...
*October 20, 2014*

**Physics**

A 27.9 kg block (m1) is on a horizontal surface, connected to a 5.3 kg block (m2) by a massless string. The pulley is massless and frictionless. A force of 239.3 N acts on m1 at an angle of 28.9°. The coefficient of kinetic friction between m1 and the surface is 0.181. ...
*October 20, 2014*

**Physics**

Starting from rest, a 98-kg firefighter slides down a fire pole. The average frictional force everted on him by the pole has a magnitude of 700 N, and his speed at the bottom of the pole is 3.4 m/s. How far did he slide down the pole?
*October 19, 2014*

**Spanish Questions?**

For 16 I think you should just do some research on what the games are like then you can find out what's different. Just google Pan American and Olympic Games and look up information on Wikipedia for comparison. The answer to 17 is the theory of natural selection. Darwin ...
*October 17, 2014*

**Algebra**

Well if you look up Cowling's rule it states:fraction of the adult dose obtained by dividing the age of the child at the nearest birthday by 24 (source internet dictionary). So let's let the age of the child be represented by the variable x. so x/24 is the fraction of ...
*October 17, 2014*

**algebra 1**

I think you may have messed up on your signs a tad because you added 18 to both sides instead of subtracting it. 18-3w=4 +3w +3w -4 -4 You can add over the 3w to make it positive and subtract the four from the 18 like so 18-4=3w 18-4 simplifies to 14 so 14=3w now divide by 3 ...
*October 17, 2014*

**Physics**

A marble rolls off a lab table that is 0.92 m high. It rolls off the table with a velocity of 1.66 m/s. How far from the base of the table must the chip be placed so that the marble will hit the chip?
*October 17, 2014*

**Calculus**

Looks good
*October 17, 2014*

**S.S**

You can find the answers to these questions online just by googling them.
*October 17, 2014*

**Physics - Spring Gun**

A toy gun uses a spring to shoot a ball with a mass of 5.0 g. The spring is “loaded” by compressing it 5.0 cm and has a spring constant of 288 N/m. The end of the spring is at the end of the gun (the ball does not travel any distance inside the gun after the spring) ...
*October 13, 2014*

**Soil Science (PAW), HELP!!**

a) If the silty clay loam soil profile is 1 meter deep, how much plant available water (cm) can potentially be held in the upper meter of soil? b) If the silty clay loam profile is 40 inches deep, how many inches of plant available water can potentially be held in the upper 40...
*October 12, 2014*

**pre-calculus**

You are given a pair of equations, one representing a supply curve and the other representing a demand curve, where p is the unit price for x items. 80 p + x - 380 = 0 and 84 p - x - 40 = 0 a. Identify which is the supply curve and demand curve and the appropriate domain. Put ...
*October 10, 2014*

**College Science **

A chandelier is suspended by two identical, vertical chains side by side. The chandelier's mass is m = 5.3 kg. A. If the tension in one chain is represented by T, write an expression for this tension in terms of m and g, the gravitational acceleration on the Earth's ...
*October 9, 2014*

**physics**

a particle is moving in a straight line the particle starts with speed 5ms and accelerates at a constant rate of 2ms for 8s it then decelerates at a constant rate coming to rest in a further 12s find the total distance during 20s it is 230 but i dont understand how
*October 9, 2014*

**Physics**

A block of wood of mass 1.2kg initially at rest is free to slide on a horizontal surface. A bullet of mass 100g travelling at a speed of 780ms^-1 is fired horizontally at the block and becomes embedded in it. Calculate the speed the block and bullet move off at immediately ...
*October 8, 2014*

**Math**

840
*October 8, 2014*

**chemistry 112**

A volume of 60.0mL of aqueous potassium hydroxide (KOH) was titrated against a standard solution of sulfuric acid (H2SO4). What was the molarity of the KOH solution if 19.2mL of 1.50 M H2SO4 was needed? The equation is 2KOH(aq)+H2SO4(aq)→K2SO4(aq)+2H2O(l) Express the ...
*October 7, 2014*

**Social Studies**

It is B Guys
*October 6, 2014*

**Algebra**

the points (1,4), (3,8) and (8,3) lie on the graph whose equation is of the form: y=a|x-b|+c where a,b and c are real numbers. find a,b and c.
*October 5, 2014*

**global studies**

Nobles
*October 5, 2014*

**physics**

The second part of the problem can be solved through the following method: Ki+Ui=Kf+Uf, which indicates that the inital KE+initial PE=final KE+ final PE. Because there is no inital KE or final PE, those values will both be zero. You are then left with just mgh=1/2 mv^2. You ...
*October 2, 2014*

**Biology**

What are some of the reasons why everyone does not have the same pulse rate at rest. I think is would be your age, weight,stress.. but i am not sure
*October 1, 2014*

**Biology**

A 50 year old male who is not overweight and has normal blood cholesterol levels suffers a heart attack. Propose a possible explanation i think the answer would be genetics...
*October 1, 2014*

**Chem (general)**

Thank you so much for the help Dr. Bob222! I was thinking there wouldn't be anything left since it was the limiting reactant but just wanted to make sure . Thanks again!!
*October 1, 2014*

**Chem (general)**

Little confused on how to get part B. A) if 3.00g of hydrosulfuric acid is reacted with 3.00g of silver nitrate, calculate the mass (in g) of solid silver sulfide formed. Which is the limiting reactant? (Hint: the other product is nitric acid). B) calculate the moles of EACH ...
*October 1, 2014*

**math**

write a ratio in 3 ways, comparing the first quantity to the second. A week has 5 school days and 2 weekends. Second question about 1 in 4 people swims at least 6 times each year.
*September 29, 2014*

**geometry**

Obtuse angle
*September 29, 2014*

**physics**

A bullet is fired straight up from a gun with a muzzle velocity of 214 m/s. Neglecting air resistance, what will be its displacement after 8.2 s? The acceleration of gravity is 9.8 m/s2 . Answer in units of m
*September 28, 2014*

**Science-HELP?**

thank you ms. sue and damon
*September 26, 2014*

**Science-HELP? **

A map of Florida is an example of a(n) ________. *I researched this a little bit and I thought it might be peninsula. Can someone verify this for me please? There aren't any choices either.
*September 26, 2014*

**Physics**

Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 1.9-kg projectile from rest to a speed of 5.1 × 103 m/s. The net force accelerating the projectile is 8.6 × 105 N. ...
*September 25, 2014*

**Math**

Scores on a marketing exam are known to be normally distribute with mean and standard deviation of 60 and 20, respectively. The syllabus suggests that the top 15% of the students will get an A in the course. What is the minimum score required to get an A?
*September 25, 2014*

**Oceans**

(I think I'm supposed to use residence time?) About 30,000 years ago, during the last glacial maximum, glaciers and ice sheets stored enough water to decrease the sea level by 120 m. Presently, there are about 3.05x106 km3 of ice contained within the Greenland glacial ...
*September 25, 2014*