Tuesday

October 25, 2016
Total # Posts: 562

**Science**

The law of conservation of energy states that energy can neither be created nor destroyed. In many instances it may look as though energy is gained or lost, but it is really only changed in form. How is the law of conservation of energy represented when an archer shoots an ...

*January 5, 2011*

**Physics**

For Part B, do (340+200)/2=270 rpm to find the average rpm during acceleration. Then divide this answer by 60 seconds to find the average revolutions per second during acceleration 270/60=4.5 rev/sec. Multiply this answer by the amount of seconds it takes for it to accelerate ...

*December 11, 2010*

**Physics**

Ball, with a weight of 200 grams, tied to a string rotates around in a horizontal plane. Period of rotation is 2 seconds. What is the force (in N) which acts on the string? The length of the string is 0.5 meters.

*December 8, 2010*

**Math **

how long does it take for a deposit of $1400 to double at 7% compounded continously it would be awesome if you could also tell me how to do it...

*November 9, 2010*

**calculus**

a) -2(x/r) b) Negative c) 2(4.29 / 6400) * 100

*November 9, 2010*

**physics**

Can you figure it out now?

*October 19, 2010*

**physics**

Velocity is a vector quantity, meaning it has both magnitude and direction. Acceleration is the rate of the change of velocity. Therefore, if the speed changes, the object is accelerating (whether it speeds up or slows down). ALSO- if the object is changing direction, the ...

*October 19, 2010*

**Physics**

For this problem, ignore air resistance. You are to fire a rifle that shoots a particular bullet at 460 m/s at a target that is 45.7 m away and level with the rifle. Assuming that the acceleration due to gravity is 9.80 m/s², how high above the target must the barrel of ...

*October 7, 2010*

**physics**

Kinematics Equations: Vx1 = Vx0 + axΔt (Vx1)^2 = (Vx0)^2 + 2axΔx Δx = Vx0Δt + ½ ax(Δt^2) Using the second kinematics equation, we can solve for Δx. (Vx1)^2 = (Vx0)^2 + 2axΔx Plug in what you know: (45 m/s)^2 = (0 m/s) + 2(9.8m/s^2)(? m...

*October 6, 2010*

**science physics**

The speed at which the two objects are approaching each other (from the trains' perspective) is 95 km/h (x 2) = 190 km/h. If they are 7.5 km apart at first, you can set up a proportion: 190 km 7.5 km ------ = --------- 1 hr x hr Cross-multiply the terms and set them equal ...

*October 6, 2010*

**Physics**

For this problem, ignore air resistance. You are to fire a rifle that shoots a particular bullet at 460 m/s at a target that is 45.7 m away and level with the rifle. Assuming that the acceleration due to gravity is 9.80 m/s², how high above the target must the barrel of ...

*October 6, 2010*

**Physics**

I would like to forget the upward component, as the object IS in fact a bullet fired at a fast velocity from a gun towards a target not too far away. However, we're graded on the correctness of our problem solving. And, additionally, this factor WOULD become an issue if we...

*October 6, 2010*

**Physics**

That's not entirely correct... That would only be true if the rifle was fired horizontally, giving the x component 460 m/s towards the target. However, that 460 m/s has some UPWARD y component too, reducing the x component by some amount... Thanks, Steven

*October 6, 2010*

**Physics**

For this problem, ignore air resistance. You are to fire a rifle that shoots a particular bullet at 460 m/s at a target that is 45.7 m away and level with the rifle. Assuming that the acceleration due to gravity is 9.80 m/s², how high above the target must the barrel of ...

*October 6, 2010*

**Physics**

Kinematics Equations: Vx1 = Vx0 + axΔt (Vx1)^2 = (Vx0)^2 + 2axΔx Δx = Vx0Δt + ½ ax(Δt^2) Had the distance from the intersection when braking begins not been given: Remaining distance = 140.0 m Current Velocity = 14.8 m/s Reaction time = 0.440 s ...

*October 6, 2010*

**science**

what is the defination of a compound machine?

*September 20, 2010*

**physics**

A 55 kg student traveling in a car with a constant velocity has a kinetic energy of 1.6 104 J. What is the speedometer reading of the car in km/h?

*September 17, 2010*

**Math**

distance problem suzi drove home at 60mph,but her brother jim,who left at the same time, could drive at only 48mph. When suzie arrived, jim still had 60 miles to go. How far did suzi drive?

*September 14, 2010*

**MATH**

2 tens 5 hundreds

*September 13, 2010*

**chemistry**

Why is the energy for high 2/5 of the energy for the low.

*June 30, 2010*

**Math**

a walk up a hill starts at a car park on the 100m contour and climbs steadily to a summet at 240m. on a map with scale 1:25000 the distance along the path from the car park to the summet is 9.6cm. how long it will to reach su,,it and back according to Naismith's rule.

*June 20, 2010*

**statistics**

A canidatate for governor of a certain state claims to be favored by at least half of the voters. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis? A. There is not sufficient evidence to reject the claim > or = 0.5 B. ...

*June 12, 2010*

**ALGEBRA**

auren and Andrew left Austin at the same time. Lauren traveled east at an average speed of 50 miles per hour. Andrew traveled west at an average speed of 65 miles per hour. How many hours of driving does it take for the two to be at least 500 miles apart? Write an inequality ...

*May 26, 2010*

**Algebra**

An elevator went to the do of a 180m building, stayed for 1 minute, then came down. The total time was 3.5 minutes. If the speed of the elevator when it went up was 1 m/sec less than when it came down, find both speeds (up and down).

*May 20, 2010*

**Algebra**

Thhe members of a soccer team are to share the $540 cost of a banquet. When 5 students are unable to attend the cost per student was $1.50 greater. How many students attended the banquet?

*May 20, 2010*

**algebra**

One paving machine can surface 1 km of highway in 6 hours. Another can surface 1 km of highway in 8 hours. how long would it take to surface 1 km of highway with the two machines working together?

*May 20, 2010*

**physics**

A 100 kg mass starts from rest at the top of an incline plane that makes an angle of 35 degrees with the horizontal. There is a coefficient of friction of 0.005 between the ramp and the mass. The mass slides down the ramp and then slides to a stop on a surface that the ...

*May 14, 2010*

**physics**

A 29 g ice cube at 0.0°C is added to 110 g of water in a 62 g iron cup. The cup and the water have an initial temperature of 25°C. (a) Find the equilibrium temperature of the cup and its contents. i don't understand how the iron cup changes the situation. please help.

*April 26, 2010*

**psychology**

Sexual arousal in human begins is different from that of other animals. It is clear that human sexual arousal can occur:

*April 23, 2010*

**algebra 1**

can u please help me figure out the estimated talk time of 250minutes

*April 22, 2010*

**statistics**

we developed a 95% z confidence interval for the mean BMI of women aged 20 to 29 years, based on a national random sample of 654 such women. we assumed there that the population standard deviation was known to be 7.5. in fact the sample data had mean BMI of 26.8 and standard ...

*April 20, 2010*

**statistics**

at the census bureau web site you can find the percent of adults in each state who have at least a bachelors degree. it makes no sense to find the mean for these data and use it to get a confidence interval for the mean percent U in all 50 states. Why not?

*April 14, 2010*

**statistics**

if young men thought that their own level of muscle was about what women prefer, the mean "muscle gap" in the study would be 0. we suspect that young men think women prefer more muscle than they themselves have. a)what is the value of he test statistic Z? b)you can ...

*April 13, 2010*

**penniman**

what is the estimate quotient for 233 divided by 6?

*March 30, 2010*

**chemistry **

identify the atoms that are being oxidized and reduced.. 2FeCl3 + 2KI --> 2FeCl2 + 2KCl + I2

*March 29, 2010*

**statistics**

in a test for esp a subject is told that cards the experimenter can see but he cannot contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has ...

*March 24, 2010*

**statistics**

a binomial distribution will be approximately correct as a model for one of these two sports settings and for the other. explain why by briefly discussing both settings. a)a national football league kicker has made 80% of his field goal attempts in the past. this season he ...

*March 24, 2010*

**statistics**

slot machines are now video games, with outcomes determined by random number generations. in the old days, slot machines were like this: you pull the lever to spin 3 wheels; each wheel has 20 symbols, all equally likely to show when the wheel stops spinning; the three wheels ...

*March 23, 2010*

**stats**

slot machines are now video games, with outcomes determined by random number generations. in the old days, slot machines were like this: you pull the lever to spin 3 wheels; each wheel has 20 symbols, all equally likely to show when the wheel stops spinning; the three wheels ...

*March 23, 2010*

**stats**

you have torn a tendon and are facing surgery to repair it. the surgeon explains the risk to you: infection occurs 3% of such operations, the repair fails in 14%, and both infection and failure occur together in 1%. what percent of these operations succeed and are free from ...

*March 23, 2010*

**math**

So would the ordered pair be (1,4)?

*March 21, 2010*

**math**

Solve using elimination method x+5y=21 -x+5y=19

*March 21, 2010*

**math of investment**

Jane will win at least $5

*March 20, 2010*

**Chemistry**

Copper(II) chloride and lead(II) nitrate react in aqueous solutions by double replacement. Write the balanced chemical equation, the over all ionic equation, and the net ionic equation for this reaction. If 16.06g of copper(II) chloride react, what is the maximum amount of ...

*March 16, 2010*

**chemistry**

What volume of 0.123 M K3PO4 is required to react with 60 mL of 0.862 M MgCl2 according to the equation 2K3PO4+3MgCl2--> Mg3(PO4)2+6KCl Answer in units of mL.

*March 10, 2010*

**physcis**

23meters

*March 4, 2010*

**How can blood type A donate to AB???**

I know my reasoning is flawed but I just can't figure out in what sense is it flawed. once again, if I apply my logic... type O has no antigens and A and B antibodies. IF you donate type O to type A, B, or AB, it wouldn't work! cuz the A and B antibodies from type O ...

*February 10, 2010*

**How can blood type A donate to AB???**

From my understanding, blood type A has A antigens and B antibodies. Blood type AB has A and B antigens and no antibodies. If someone donates type A to type AB, wouldn't the antibody B from type A attack the antigens B from AB??? I know I am looking at this incorrectly but...

*February 10, 2010*

**Propagation of error and sig. figs**

To summarize my messy post, I am unsure how to write my final answer

*January 22, 2010*

**Propagation of error and sig. figs**

I'm really embarrassed to ask this! I knew how to do it before but I forgot after 2 years. I remember learning it for analytical chemistry :( So a basic problem: What is x= a+b+c? given that: a= 100.7 +/- 0.05 b= 0.61 +/- 0.005 c=226 +/- 0.5 OK. My question is the ...

*January 22, 2010*

**english**

What nursery rhyme character was a "wise galoshes wearing feline" answer has 12 letters.

*January 20, 2010*

**4th grade**

What is matter made up of?

*January 17, 2010*

**science**

Does lighting occur when charges jump between the thunder cloud and the positive ground as a discharge?

*January 16, 2010*

**Science**

Is discharge of static electricity from a huge cloud called a thundercloud?

*January 16, 2010*

**4th grade**

Is all matter made up of tiny particles too small to see

*January 16, 2010*

**math**

if the altitude of a triangle is doubled and the base is multiplied by 3,what is the effect on the area?

*January 12, 2010*

**accounting**

You are provided with the following transactions that took place during a recent fiscal year. Complete the table indicating whether each item (1) should be reported as an operating (O) activity, investing (I) activity, financing (F) activity, or as a noncash (NC) transaction ...

*December 7, 2009*

**Calculus**

Suppose a cylindrical can is manufactured with radius r. The manufacturing process makes the length r imprecise; r can be off by ±0.03 cm. The manufacturing process makes the height of the can precisely equal to three times the radius r (including any error in r, but ...

*December 4, 2009*

**algebra**

72 students is 90% of how many students

*November 17, 2009*

**math**

Find the percent using the percent proportion 75 rolls is what percent of 1000 rolls

*November 17, 2009*

**math**

Identify the percent,whole , and part in the following 30% of 730 is 219 do not solve for any unknowns Percent= Whole= Part=

*November 17, 2009*

**math**

A michigan orchard made 11,491lb of taffy apples with approximately 1lb of taffy mixture for each 76.7 pounds of apples. To the nearest tenth of a pound, how many pounds of apples and how many pounds of taffy were used

*November 16, 2009*

**MO theory regarding heteronuclear diatomic molecul**

Hi all I am having trouble finding the MO order for heteronuclear diatomic molecules: In my textbook, heteronuclear order is listed as: 1o 2o 3o 4o 1pi 5o 2pi 6o where o = sigma When I first saw it, I was confused; how can the above be correct? If one were to calculate bond ...

*November 11, 2009*

**11th grade chemistry**

how many molecules do you have in 64g of CO?

*November 11, 2009*

**Term symbols for ground states**

Dr Bob, Thank you so much!! You have taught me something in mere minutes that my professor failed to do in a single lecture. And thank you again for the web site. I had no idea such a site existed! I wish there was a karma/rep system :) thanks again

*November 5, 2009*

**Term symbols for ground states**

OHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH. if it was 8e- in d orbitals (5 of em) it would be +2 +1 0 -1 -2 for up spin , then +2 +1 and 0 for down spin! therefore, total is 3 and L=3!!!! I hope this is correct!

*November 5, 2009*

**Term symbols for ground states**

Thank you Dr Bob. Yes, I am seriously confusing myself haha As far as the 4d8 is concerned, I was referring to Ni2+ it has 8 electrons it occupies 2, 1, 0, -1, -2 so would that make L = 0 which is S? Sorry for the confusion. I greatly appreciate you staying and helping me ...

*November 5, 2009*

**Term symbols for ground states**

what about Nb2+ then? it has 8 electrons it occupies 2, 1, 0, -1, -2 so would that make L = 0 which is S?

*November 5, 2009*

**Term symbols for ground states**

But for Nb2+ where it is 4d^3 Shouldn't L be D instead of F? Like p^2 in carbon, L = P And in s^2, L = S ------ Or am I going about this the wrong way?

*November 5, 2009*

**Term symbols for ground states**

You are correct DrBob. Error on my part.

*November 5, 2009*

**Term symbols for ground states**

I have having difficulty understanding where L comes from in term symbol notation For Carbon, e- configuration is 1s^2 2s^2 2p^2 p corresponds to l=1 overall spin is 3/2 since cell is less than half-full, J=S=3/2 so term symbol is 4 P (3/2) this i understand where P came from...

*November 5, 2009*

**Quantum mechanics, eigenvalues, eigenfunctions**

I'll also like to thank Dr. Physics for helping me last time :)

*October 22, 2009*

**Quantum mechanics, eigenvalues, eigenfunctions**

What exactly is an eigenvalue? "To be an eigenfunction, the operator has to reproduce the function with some multiplicative constant." Is the eigenvalue the multiplicative constant -or- is it the m constant and the function? Many thanks.

*October 22, 2009*

**statistics**

A certain airplane has two independent alternators to provide electrical power. The probability that a given alternator will fail on a 1-hour fight is .02. What is the probability that (a) both will fail? (b) Neither will fail? (c) One or the other will fail? Show all steps ...

*October 9, 2009*

**Quantum mechanics, eigenfunctions!**

Thank you! I thought I was going crazy because I wasn't able to an eigenfunction since 1st deriv. would be = cos(x)*e^(ax) + a*sin(x)*e^(ax) which is definitely not an eigenfunction of the operator.

*October 8, 2009*

**Quantum mechanics, eigenfunctions!**

Determine if the function sin(x)*e^(ax) where a=constant is an eigenfunction of the operators d/dx and d^2/(dx)^2 Okay. My understanding is that you use the operator and perform its "thing" on the function. In this case, you will have to find the 1st derivative of ...

*October 8, 2009*

**social studies**

what imapct did the enstablishment of french and dutch coloies in north america have on native americans?

*September 29, 2009*

**6th grade**

How did Canadian Inuits make their decisions. Also did the have a leader or chief and how were they chosen

*September 26, 2009*

**biology**

identify what all organic compounds have in common,and list the four principal classes of or organic compounds

*September 23, 2009*

**Physics AP C**

Two trains, each having a speed of 22 km/h, are headed at each other on the same straight track. A bird that can fly 60 km/h flies off the front of one train when they are 70 km apart and heads directly for the other train. On reaching the other train it flies directly back to...

*August 26, 2009*

**Fundamental Cornerstones of Managerial accounting**

Green Enterprises produces small engines for lawn mowers. during the year, 110,000 engines were produced. The actual labor used was 60,000 hours at $9.50 per hour. Green has the following labor standard: 0.5 hour at $10 1. compute the labor rate variance. 2. compute the labor ...

*July 30, 2009*

**Chemistry**

Write the net ionic equation for silver nitrate and sodium chloride. I only know how to do it when it deals with elements, not compound.

*July 23, 2009*

**math**

x*y=50 x/y=2 10*5=50 10/5=2

*July 19, 2009*

**math**

A right triangle has a hypotenuse of length 3.00 m, and one of its angles is 30.0°. What are the lengths of (a) the side opposite the 30.0° angle and (b) the side adjacent to the 30.0° angle?

*July 19, 2009*

**math**

A painting measuring 100cm by 55cm is to be framed with a matte border of uniform width surrounding the painting. the combined area of the picture and the matte is 9796cm^2. How wide is the matte border?

*July 12, 2009*

**math**

A rectangular field is to be enclosed by a fence. Two fences parallel to one side of the field divide the field into three rectangular fields. If 2400m of fence are available find the dimensions giving the max area.

*July 12, 2009*

**math**

solve for x 3x^2-18x=0

*July 12, 2009*

**grade 11 math**

a uniform-width boardwalk is built around the inside edge of a rectangular parkland that is 10m by 15 m. if the boardwalk takes up 20% of the lot, how wide is the boardwalk to the nearest centimetre?

*July 7, 2009*

**Physical Science**

what grade is this

*May 22, 2009*

**Math**

Today's HW, due tomorrow, I'm lost, please help. 1. 5y - 7x = 10 2. 2y = 10 - 2 (x - 3) 3. y = 2x + 1/2 (3x + 1) + 1/4 (2x + 8)

*May 4, 2009*

**Physics**

If two pith balls - one which is neutral and another which has a charge of -9.6 uC (micro-Coulombs) - are touched together, how many extra electrons will each ball have?

*April 8, 2009*

**CHEM HELP**

Which of the following is NOT true of colligative properties? Colligative properties are... a) dependent on the molar mass of the solute. b) dependent on the mass of solute present. c) responsible for lowering the vapor pressure of a solution versus the vapor pressure of the ...

*April 2, 2009*

**math: factoring**

how would i factor this 2x^2(p + q^3) - (p + q^3)

*March 20, 2009*

**MATH**

I NEED TO FIND WHAT 33333+12=

*March 9, 2009*

**MATH**

END 1045PM ELAPES TIME 12HR 35MIN FIEN WHEN STARTED

*March 9, 2009*

**college chemistry**

I got 1)Potassium persulfate 2)persulfate ion 3)Sodium thiosufate 4)thiosulfate ion

*February 25, 2009*

**college chemistry**

How do I name the following compounds; K2S2O8, S2O8{-2}, Na2S2O3 and S2O3{-2}

*February 25, 2009*

**Chemistry**

The mol mass calculated would be higher than expected. but when we are measuring the pure cyclohexane's freezing point, this wouldn't matter right?? The freezing point would be the same no matter what the volume of solvent.

*February 25, 2009*

**mathematics**

For each of the following state the axiom, definition illutrated. All elements written are whole numbers. v-e= s since e< v and s + e = v

*January 25, 2009*