Tuesday

October 25, 2016
Total # Posts: 197

**physics**

The speed of sound in air is approximately 340 m/s. The speed of sound in steel is approximately 5900 m/s. If your friend strikes one end of a steel pipe with a hammer while you listen at the other end, you will hear two distinct sounds: one traveling through the air and the ...

*October 12, 2016*

**Physics **

Describe the steps necessary to convert a parabolic decreasing curve to a liner graph. That's is one with the relationship between two variables give a straight line.

*October 2, 2016*

**chemistry**

Calculate the value of q for each of the experiments listed below. (Assume the heat capacity of water is 4.1801 J/g*C). Exp1: 2.48g of an unknown salt added to 160. mL of water resulted in a change of temperature of -0.1 C. Exp2: 2.48g of an unknown salt added to 160. mL of ...

*July 7, 2014*

**Intermediate Algebra**

A basketball team recently scored a total of 95 points on a combination of 2-point field goals, 3-point field goals, and 1-point foul shots. Altogether, the team made 54 baskets and 16 more 2-pointers than foul shots. How many shots of each kind were made? How many 1-point ...

*February 20, 2014*

**pllllls heeeeeeeeelp math**

In the image the equals sign is a typographical error

*June 6, 2013*

**pllllls heeeeeeeeelp math**

How do you proceed after that?

*June 6, 2013*

**Math**

Can you show and easy way to show this formula in the form of an equation Example: a = b × r/100

*May 27, 2013*

**physics**

An underwater micriphone is used to record sounds emitted by porpoises. The minimum intensity level the instrument can record is 30.9dB. Assuming a porpoise emits sound at a rate of 0.0603J/s, what is the maximum distance at which the animal will still be recorded? Neglect ...

*April 9, 2013*

**physics**

An underwater micriphone is used to record sounds emitted by porpoises. The minimum intensity level the instrument can record is 30.9dB. Assuming a porpoise emits sound at a rate of 0.0603J/s, what is the maximum distance at which the animal will still be recorded? Neglect ...

*April 9, 2013*

**physics**

An underwater micriphone is used to record sounds emitted by porpoises. The minimum intensity level the instrument can record is 30.9dB. Assuming a porpoise emits sound at a rate of 0.0603J/s, what is the maximum distance at which the animal will still be recorded? Neglect ...

*April 9, 2013*

**physics**

An underwater micriphone is used to record sounds emitted by porpoises. The minimum intensity level the instrument can record is 30.9dB. Assuming a porpoise emits sound at a rate of 0.0603J/s, what is the maximum distance at which the animal will still be recorded? Neglect ...

*April 9, 2013*

**physics**

An underwater micriphone is used to record sounds emitted by porpoises. The minimum intensity level the instrument can record is 30.9dB. Assuming a porpoise emits sound at a rate of 0.0603J/s, what is the maximum distance at which the animal will still be recorded? Neglect ...

*April 9, 2013*

**physics**

An underwater micriphone is used to record sounds emitted by porpoises. The minimum intensity level the instrument can record is 30.9dB. Assuming a porpoise emits sound at a rate of 0.0603J/s, what is the maximum distance at which the animal will still be recorded? Neglect ...

*April 9, 2013*

**Biology - Uncertainty (Repost)**

I'm doing a bio lab, and I have collected data on heart rate measured in beats/15 secs with an uncertainty of +/- 1 beat/sec. To get heart rate per minute, I multiplied my data by 4, making my uncertainty +/- 4 beats/min. However, what I need to do now is some subtraction...

*February 10, 2011*

**Biology - Uncertainty**

I'm doing a bio lab, and I have collected data on heart rate measured in beats/15 secs with an uncertainty of +/- 1 beat/sec. To get heart rate per minute, I multiplied my data by 4, making my uncertainty +/- 4 beats/min. However, what I need to do now is some subtraction...

*February 9, 2011*

**Math**

PLEASE!

*January 12, 2011*

**Math**

I need an example of the Associative property.

*January 12, 2011*

**French**

I've been given an article and some questions to answer. One of them is: "Au paragraphe deux que veulent dire les mots... a) enjeux b) nouvelle" I can't figure out what the question is asking me to do with those two words.

*October 6, 2010*

**French**

I want to translate this phrase into French: "When I can no longer create anything, I'll be done for." -Coco Chanel How would I translate the expression "I'll be done for"?

*September 16, 2010*

**Physics**

"At what point between two masses of 20kg and 15kg located 1.0m apart, will the gravitational field strength equal zero?"

*July 29, 2010*

**Physics**

"A workman sitting on top of a roof of a house drops his hammer. The roof is smooth and slopes at an angle of 30.0 degrees to the horizon. It is 32m long and its lowest point is 32m from the ground. How far from the house's wall is the hammer when it hits the ground?&...

*July 29, 2010*

**Physics - Another Question**

"Three forces act at a single point. Two of the forces are 39N southwest and 45N north. What is the value of the third force that creates equilibrium?"

*July 28, 2010*

**Physics**

"Two wooden blocks A and B have respective masses of 3.0kg and 4.0kg and are connected with an inextensible cord. If the blocks are placed on a horizontal frictionless surface and a force of 8.0N is applied to A, find the tension in the connecting cord."

*July 28, 2010*

**Physics**

"A mass of 3.08kg oscillates on the end of a horizontal spring with a period of 0.323s. What acceleration does the mass experience when its displacement is 2.85m to the right?"

*July 26, 2010*

**Physics**

"Determine the restoring force of a pendulum that is pulled to an angle of 12.0 degrees left of the vertical. The mass of the bob is 300.0g."

*July 26, 2010*

**Never mind!**

Thanks, but I figured it out.

*July 25, 2010*

**Physics**

"Water flows over a section of Niagara Falls at the rate of 1.2*10^6 kg/s and falls 50.0m. How much power is generated by the falling water?" It's a the kg/s that is confusing me. I don't know how to work with it.

*July 25, 2010*

**Physics**

"A wave travels from one medium to another, and the wavelength decreases. What happens to the velocity and the frequency?" I know that frequency will remain the same, because it is controlled only by the source. But does the velocity decrease? According to Snell'...

*July 22, 2010*

**Physics**

Ah! Thank you so much!

*July 21, 2010*

**Physics**

"Point S1 and S2 are close sources of circular water waves each of wavelength 6.0cm. P is a point some distance away from the sources. Explain whether the following path differences (path difference = PS2 - PS1) result in nodes or anti-nodes. a) 6.0cm b) 9.0cm c) 18cm d) ...

*July 21, 2010*

**Physics**

Thank you so much!

*July 21, 2010*

**Physics**

"Vibrators A and B are sources of waves with different wavelengths and they are placed close to one another in a ripple tank. Waves from source A have a wavelength of 8.0cm while those from B have a wavelength of 10cm. The waves start out in phase with each other. For ...

*July 21, 2010*

**Physics - Another Question**

"A meter stick is held vertically behind an object on a spring. The object vibrates from the 20cm mark to the 32cm mark on the stick. Find the displacement when the object is at the 20cm mark, 24cm mark, 26cm mark, and 30cm mark." I had found the equilibrium position...

*July 20, 2010*

**Physics**

"What happens to the energy associated with a wave after the wave has been damped out?" I'm assuming all the energy is lost by then, am I right?

*July 20, 2010*

**Physics**

Thank you!

*July 19, 2010*

**Physics**

"Two springs are hooked together and one end is attached to a ceiling. Spring A has a spring constant of 25N/m, and spring B has a spring constant of 60N/m. A mass weighing 40.0N is attached to the free end of the spring system to pull it downward from the ceiling. What ...

*July 19, 2010*

**Never mind!**

Thanks, I got it.

*July 17, 2010*

**Physics**

"Two masses, 2000kg and 5000kg, are placed 20m apart. A third mass of 5000kg is placed in between the two large masses a distance of 5.0m from the larger mass. What is the force acting on the 500kg mass?"

*July 17, 2010*

**Physics**

"If a small planet were located 8 times as far as the Earth's distance from the Sun, what would be its period in Earth years?" (22.5 earth years) As a note, we are given a table with all of the planets' masses and radii.

*July 15, 2010*

**Never mind!**

Thanks, but I got it.

*July 14, 2010*

**Physics**

"An athlete whirls a 3.7kg shot-put in a horizontal circle with a radius of 0.90m. If the period of rotation is 0.30s, how far would the shot-put travel horizontally if it is released 1.2m above the level ground?" There were two other parts to the question that I had...

*July 14, 2010*

**Physics**

Oh thank you so much!

*July 12, 2010*

**Physics**

"A roller coaster reaches the top of the steepest hill with a speed of 1.4m/s. It then descends the hill which is at an average angle of 45 degrees and is 50m long. What will its speed be when it reaches the bottom?"

*July 12, 2010*

**Physics**

I figured it out, thank you!

*July 12, 2010*

**Physics**

"A 5000kg helicopter accelerates upwards at 0.50m/s^2 while lifting a 2000kg car. What is the lift force exerted by the air on the propellers?" I don't understand what the problem is asking for.

*July 12, 2010*

**Physics - Another Question**

"Two girls, one of mass 40kg and the other of mass 60kg, are standing side by side in the middle of a frozen pond. One pushes the other with a force of 360N for 0.10s. The ice is essentially frictionless. What is each girl's acceleration?"

*July 12, 2010*

**Physics**

Thank you for answering both questions! I understand them now.

*July 12, 2010*

**Physics**

"A fish hangs from a spring scale supported from the roof of an elevator. If the elevator has an upward acceleration of 1.2m/s^2 and the scale reads 200N, under what circumstances will the scale read 150N? What will the scale read if the elevator cable breaks?" There...

*July 12, 2010*

**Physics**

I'm learning about Newton's Laws of Motions and I'm having trouble understanding these questions: "A rear-end collision between a soft-drink truck and a car occurs. The truck driver claims the car backed into him, while the auto driver claims that the truck ...

*July 8, 2010*

**Physics - Another Question**

Oh, thank you drwls!

*July 7, 2010*

**Never Mind!**

Sorry, I figured it out!

*July 7, 2010*

**Physics - Another Question**

"An airplane if flying level at 80.0m above the ground with a speed of 350km/h. The bombardier wishes to drop food and medical supplies to hit a target on the ground. At what horizontal distance from the target should the bombardier release the supplies?"

*July 7, 2010*

**Physics - Projectile Motion**

Ah, I see! Thank you!

*July 7, 2010*

**Physics - Projectile Motion**

"A person fires a bullet horizontally from a gun at the same instant that another bullet is dropped from the same height as the rifle barrel. Discuss which bullet will hit the ground first." I'm thinking that the bullet that is dropped will hit first, because it ...

*July 7, 2010*

**Physics**

"An airplane is climbing at an angle of 15 degrees to the horizontal with the sun directly overhead. The shadow of the airplane is observed to be moving across the ground at 200 km/h. How long does it take for the plane to increase its altitude by 1000 m"? There was ...

*July 6, 2010*

**Physics**

"An object is rolled up an incline. If the object is 2.75 m up the incline after 4.50s and rolling back down at a velocity of 1.90 m/s, what is the acceleration of the object?" Is this a case of final velocity - initial velocity?? It seems like an easy problem, but I...

*July 5, 2010*

**Physics**

Thank you! I got it!

*July 5, 2010*

**Physics**

"A diver springs upward with an initial speed of 1.8 m/s from a 3.0 m board. Find the velocity with which the diver strikes the water." Help please!

*July 5, 2010*

**Calculus**

Oh I see! Thank you!

*June 20, 2010*

**Calculus**

"The illumination of an object by a light source is directly proportional to the strength of the source and inversely proportional to the square of the distance from the source. Two streetlights are 40m apart and one is twice as strong as the other. Where is the darkest ...

*June 20, 2010*

**Algebra--One Quick Question**

I say A. This is not a geometric sequence. It's arithmetic.

*June 18, 2010*

**Calculus**

Thank you both!

*June 18, 2010*

**Calculus**

"Differentiate x^(x^3)" I can do it when the base is a number, but I'm confused as to how to do it with x as the base.

*June 18, 2010*

**Calculus **

Thank you both! However, the problem is I can't seem to visualize the diagram correctly. I can't see where the right triangle is coming from. But no worries, I will look at more example problems and see if I can figure these questions out.

*June 17, 2010*

**Calculus **

"At 9am ship A is 50 km east of ship B. Ship A is sailing north at 40km/h and ship B is sailing south at 30km/h. How fast is the distance between them changing at noon?" I can never get these type of questions where two ships are heading in different directions and ...

*June 17, 2010*

**Calculus**

"At 9am ship A is 50 km east of ship B. Ship A is sailing north at 40km/h and ship B is sailing south at 30km/h. How fast is the distance between them changing at noon?" I never know how to set questions like this up!

*June 16, 2010*

**Never Mind!**

Oops! I just found out that I don't need to know how to do this type of question.

*May 27, 2010*

**Calculus**

"Evaluate the following indefinite integral using integration by parts: *integral sign* tan^-1(x) dx" I let u = tan^-1(x) and dv = dx. Is that right?

*May 27, 2010*

**Chemistry**

"An aqueous sodium borate solution is titrated to the second endpoint with 0.225 mol/l nitric acid in the presence of a suitable indicator. If an average of 12.6mL of titrant are required to reach the second endpoint for a 25.0 mL sample, what is the base concentration?&...

*May 15, 2010*

**English - Macbeth**

In Act 3, scene 3, Macbeth sends a third murderer to help the other two murder Banquo and his son. Does the third murderer know as much about Banquo as Macbeth says he does? From what I see, it seems as if it could go either way. For example, this part: "Almost a mile, ...

*May 11, 2010*

**science/chemistry**

Dr Bob I don't like B or C or D that only leaves A Is this what you would go for ???? Thanks andy

*May 10, 2010*

**science/chemistry**

Qc for the following chemical reaction 3CIO2-(aq)<-->2CIO3-(aq)+Cl-(aq) Choices A:3[CIO2-]/2[CIO3-][Cl} B:2[CIO3-][Cl]/3[CIO2-] C:[CIO2-]^3/[CIO3-]^2[Cl-] D:[CIO3-]^2[Cl-]/[CIO2-]^3 I like B: what would you go for?? thanks all

*May 10, 2010*

**CHEMISTRY!!**

Thanks Dr BOB !!!!!! Andy

*May 10, 2010*

**CHEMISTRY!!**

Yes the text book says and I quote: V=nRT/P=(1.000mol)(8.314kPa L/mol K)(273.15 K)/100kPa=22.71L This is the molar volume of any ideal gas at STP.(if non-si units of atmospheres and the gas constant value of 0.08206 atm L/mol are used , the value is 22.41 L Hope that helps... ...

*May 10, 2010*

**CHEMISTRY!!**

2.27 sounds the best option It cant be 5.53 or 4.42 the maths don't add up!!! So i agree thanks

*May 10, 2010*

**Chemistry**

Ok, yes you're right. Thank you! No, I'm not. :)

*May 9, 2010*

**Chemistry**

I am designing a procedure for a lab where I have to use indicators to create an acid-base table from 6 solutions. I am just wondering...if I put a drop of indicator into a solution, do I have to dispose of it and obtain new solution before putting in another type of indicator...

*May 9, 2010*

**Chemistry**

Also, if products are favoured, does that mean that the resulting solution is basic? And if reactants are favoured, the solution is acidic? Or is there no distinction?

*May 7, 2010*

**Chemistry**

I am predicting acid-base equilibria using the Brondsted-Lowry predictions. I am asked to do "solid aluminum sulfate added to water". So I know there is an Al^2+ ion and a SO4^-2 ion, but does water dissociate into H30^+ and OH^-? If so, then H30^+ and OH^- would be ...

*May 7, 2010*

**Math - another question**

According to the binomial theorem, the term with x^2 would be the third term. I plugged my known values into the "formula" for the third term, and made it equal to 5. Then I solved for a. Sorry, my explanation is kind of vague.

*May 5, 2010*

**Never Mind!**

I got it. :)

*May 5, 2010*

**Math - another question**

"In the expansion of (2-ax)^5 the coefficient of x^2 is 5. Find the value of a". I know I have to use the binomial theorem to help me, but I don't know how.

*May 5, 2010*

**Math**

"Three of the coordinates of the parallelogram STUV are S(-2,-2), T(7,7) and U(5,15). State the vector ST and hence determine the coordinates of V." So I've figured out that ST = (9,9), but I don't see how that helps me find V.

*May 5, 2010*

**Math**

"The probability of getting heads on a biased coin is 1/3. Sammy tosses the coin 3 times. Find the probability of getting two heads and one tail". I thought that all you have to do is: (1/3)(1/3)(2/3) It makes sense to me, but it's not right...

*May 3, 2010*

**Math**

Oh yeah! Thank you!

*May 3, 2010*

**Math**

"In vase A, there are 3 red balls and 5 white balls. In vase B, there are 6 red balls and 4 white balls. Two balls are to be drawn at random, without replacement, from each vase. What is the probability of selecting 4 red balls?" (Answer: 1/28) So I thought about ...

*May 3, 2010*

**Chemistry**

Sorry. "Calculate the pH for 0.10 mol/L aqueous solution of NaCl".

*May 2, 2010*

**Chemistry**

"Calculate the pH of NaCl". I know that NaCl is neutral...but I don't know how to show that it is neutral. The ka value for the Cl ion is "very large", so what do I do?

*May 2, 2010*

**Chemistry**

DrBob, if you're still on...what do I do for NaCl??

*May 2, 2010*

**Chemistry**

Oh you're right! Thanks.

*May 1, 2010*

**Chemistry**

Ohhh! Ok! Thank you for that! I missed a class, and so I'm relying on my notes to teach me...which isn't easy. Interesting little fact btw.

*May 1, 2010*

**Chemistry**

Is the initial concentration for Al(H20)6 also 0.10 mol/L?

*May 1, 2010*

**Chemistry**

No, it doesn't. But I have it in my notes. Ok, I think I understand how to approach this. Thanks!

*May 1, 2010*

**Chemistry**

Sorry, I have a question within a question. I think the ka value for the aluminum ion is used for when we have a solution like AlCl3, right? When you dissociate it, the Cl ion has a very large ka value...so we use the ka for Al instead? I hope I'm making sense. :)

*May 1, 2010*

**Chemistry**

Oops! Sorry, I figured it out. But I still need help...I'm not clear on the process.

*May 1, 2010*

**Chemistry**

"Calculate the pH of 0.10 mol/L aqueous solution of aluminum sulfate." I am also given the ka value for the aluminum ion (9.8x10^-6)...but I don't know why I need it. I'm not even sure if I need to use it. Help please?

*May 1, 2010*

**calculus**

The manager of a large apartment complex knows from experience that 100 units will be occupied if the rent is 350 dollars per month. A market survey suggests that, on the average, one additional unit will remain vacant for each 7 dollar increase in rent. Similarly, one ...

*April 20, 2010*

**Calculus**

Sorry! I got it. I forgot that revolving around a line can change which function is outer and which is inner.

*April 18, 2010*

**Calculus**

"Find the volume of the solid generated by revolving the region bounded by the graphs of the given equations about the indicated lines: y = 2x^2 y = 0 x = 2 About the line y = 8"

*April 18, 2010*

**Calculus**

"Evaluate the following indefinite integrals: "S" (3x^2 -2)/(x^3 - 2x + 1)^3 dx" We're practicing the substitution rule, and I know how to do it, but I don't know what/how to substitute in this question. btw: "S" is the integral sign.

*April 11, 2010*