# Posts by Charlie

Total # Posts: 487

Physics ideal gases
If 2 samples of nitrogen (different PVTs) are separated by a conductive barrier, they will eventually achieve equilibrium, I believe. Am I right to assume that the final T and P at equilibrium in this case would be the SAME T and P if the barrier was highly insulated, then ...

Physics ideal gases
Thanks Damon, I realise I didn't tell you what i'm asked to do! I note your point about the start point for the equation. Thanks

Physics ideal gases
Would someone check my thinking please. PVT of an ideal gas (nitrogen) are all given. I've used PV=nRT rearranged to get the number of moles. Then, U= 3/2nRT to get the internal energy of the sample. Am I on the right track? Thanks.

Physics
For a child's swing in lightly damped SHM, I am given the time period and a value for g; (as well as the mass.) with just these, can i rearrange the equation: T (4s)= 2pi times sqrt l/g to calculate the length of the swing? I believe i have (3.98m), but the question says ...

Physics
For a child's swing in lightly damped SHM, I am given the time period and a value for g; (as well as the mass.) with just these, can i rearrange the equation: T (4s)= 2pi times sqrt l/g to calculate the length of the swing? I believe i have (3.98m), but the question says ...

Physics (checking my thinking)
Thanks both, for the answers.

Physics (checking my thinking)
Yes, it's zero. That seems to make the second term (m2u2) zero, but I still get what i think is the correct answer. What should be my next approach?

Physics (checking my thinking)
2 spheres, of unequal masses, hang on strings and are touching. Sphere a is pulled back to the left, string taught, and released, hitting sphere B at a known velocity. Sphere B's post impact velocity is known, and to the right. i have to find A's post collision ...

physics
How large a pressure increase (in ATM) must be applied to water if it is to be compressed in volume by 1%? The bulk modulus of water is 2 ~ 10^9 N/m^2 and 1 ATM = 10^5 N/m^2 I think that it is P = bulk modulus * 0.01 because 1/100 = 0.01, which is 1% of a volume. B = &#...

Physics
why 0.001? 1/100 is 0.01. I thought that was 1 %. Also is that pressure minus (-) or pressure (equals)?

Physics
How large a pressure increase (in ATM) must be applied to water if it is to be compressed in volume by 1%? The bulk modulus of water is 2 × 109 N/m2 and 1 ATM = 105 N/m2

Physics
Thanks very much, I appreciate it.

Physics
A pendulum of a given mass is pulled back through a given vertical height and released to swing back down to a 'wall' where it impacts. Can i use mg delta h to get E kin; and then use E= half mv^2 to get the collision impact velocity? Would someone check my thinking ...

Physics, Collisions
A pendulum of a given mass is pulled back through a given vertical height and released to swing back down to a 'wall' where it impacts. Can i use mg delta h to get E kin; and then use E= half mv^2 to get the collision impact velocity? Would someone check my thinking ...

Geography
Wouldn't the ground soak up the water? The sediment would come from the surrounding mountains.

Geography
I think sediment would build up on the valley floor and raise the elevation. And a lot more vegetation would grow. Am I close?

Geography
If Death Valley was located in an area with a lot of rainfall, how would the valley floor change? How would Death Valley change? Thanks!

Geology/Glaciers
Why do north facing slopes on mountains support glaciers today while south facing slopes do not?

Physics SHM
Sorry Bob, The wave represents a simple pendulum. In 3, I'm referring to the equation x(t)=Asin(wt+(greek letter phi)), so was looking to confirm that in that specific circumstance I outlined, the value of phi would either be zero or pi (as in 22/7). Thanks.

Physics SHM
Am self studying SHM, so sorry for the elementary questions. Would someone check/confirm some facts i think I've learned please. 1 If a sine wave graph starts at the origin at time = 0s, the sysyem is in equilibrium? 2 The amplitude at t= 0s is zero. 3 Same system, the ...

Physics SHM
Whether or not it'll help me, am i safe to deduce that: If a simple pendulum is released from rest at time t=0; from a displacement of x rad from equilibrium; Then the amplitude of the oscilation is also x rad? Thanks

math
what is the rest of the problem?

Physics
If a space station must "provide one sixth the magnitude of the acceleration due to gravity on Earth" Can I use 9.81ms^-2/6 or is that too simple? Thanks.

Physics/mechanics
Thank you very much

Physics/mechanics
I have to do calculations based upon a bow shooting an arrow vertically, and I have to state any assumptions i'm making. Am I right to cite air resistance as negligible; and that the displacement will start 2m above the ground (not at ground level)? The rest I'm ok with.

physics
While her kid brother is on a wooden horse at the edge of a merry-go-round, Sheila rides her bicycle parallel to its edge. The wooden horses have a tangential speed of 6 m/s. Sheila rides at 4 m/s. The radius of the merry-go-round is 8 m. At what time intervals does Sheila ...

Math
I posted another question accidentally as an answer to my question

Math
I looked at that sight and can see the tables but what I have is a table that show the heights of students in a class males on top females on bottom with heights out beside them. I have to make a cumulative frequency table from the data in my collumns I have, height,frequency ...

Math
How do you make a cumulative frequency table

college
what's the most commonly overlooked reason for forgetting?

GEOGRAPHY
please could someone help, i need to find information about broughton chester airbus to write an essay about it.i need to write about what is made there how the parts are transported to different places how big the factory is what alterations have been made to the factory. ...

CHEMISTRY
I'm struggling with this homework question...i have no idea how to set this up. We start with a 33.50 mL aliquot of acetic acid and titrate it with 0.215 M of NaOH. Find the pH at: 21.7 ML added the equivalence point i don't understand how this works. please help, ...

Physics
A spring of k=11 N/m has a block of mass 4 kg attached to it on a frictionless table. If the block is pulled a distance 0.15 m to the right and released from rest, how long will it take the block to return to its equilibrium position?

Physics
The position of some object moving along the x-axis is observed to be x(t)=9cos(pi*t/3+pi/4) meters. Find the frequency.

French Pen-Pal
Me and my french pen pal enjoy chatting about our opinions of things. Maybe one of her favourite films (?) are on of the worst in your opinion. So tell her your own opinion. We also like talking about what's in our town (where we live) and what we love to do on the weekend...

Algebra
How do you convert money to pecent?

chem
Dude, That is a freakin HAAAAARRRDDD guestion. your in colledge right??

Science
MRIs use very powerful electo magnets>

Physics
I'm still not getting the right answer. It asks to convert it to centimeters but even when I do that I am still getting it wrong.

Physics
An advertisement claims that a centrifuge can produce a radial acceleration of 3,524g at 4,608 rev/min. Calculate the required radius of the centrifuge.

Physics
An object of mass 3.5x1023kg circles the earth and is attracted to it with a force whose magnitude is given be GMeM/r^2. If the period of rotation is 22 days, what is the distance from the earth to the object? Here G=6.67x10-11 Nm2/kg2, Me=6x1024 kg.

Physics
Suppose you are driving a car around in a circle of radius 157 ft, at a velocity which has the constant magnitude of 42 ft/s. A string hangs from the ceiling of the car with a mass of 1.8 kg suspended from it. What angle (in degrees) will the string make with the vertical?

Physics
A cannon shoots a shell straight up. It reaches its maximum height, 837 feet, and splits into two pieces, one weighing 2 lb and the other 5 lb. The two pieces are observed to strike the ground simultaneously. The 5 lb piece hits the ground 1,564 feet away from the explosion (...

Physics
OK thanks. There is another part of the question that asks for the momentum of the 4 lb piece and I can't figure out how to solve that.

Physics
A cannon shoots a shell straight up. It reaches its maximum height, 1,051 feet, and splits into two pieces, one weighing 2 lb and the other 4 lb. The two pieces are observed to strike the ground simultaneously. The 4 lb piece hist the ground 1,608 feet away from the explosion...

Physics
sorry I don't know what happened but I posted it again and the question is on there.

Physics
A cannon shoots a shell straight up. It reaches its maximum height, 1,051 feet, and splits into two pieces, one weighing 2 lb and the other 4 lb. The two pieces are observed to strike the ground simultaneously. The 4 lb piece hist the ground 1,608 feet away from the explosion...

Physics
You are stranded in the middle of a frozen pond, 825 m in diameter which is so slippery that your feet slide freely and don't move you. In desperation you write an S.O.S. on your hat, mass 0.6 kg, and fling it towards the north with a velocity of 13 m/s at 54o with the ...

english
which is correct?"What a disaster,"shouted Maria. "What a disaster!"shouted Maria!

Physics
A movie stunt man (mass 82.3 kg) stands on a window ledge 5.69 m above the floor. Grabbing a rope attached to a chandelier, he swings down to grapple with the movie’s villain (mass 72.3 kg), who is standing directly under the chandelier. (Assume that the stunt man’s ...

Physics
Ice-hockey star Wayne Gretzky is skating at 12.7 m/s toward a defender, who in turn is skating at 5.39 m/s toward Gretzky. Gretzky’s weight is 677 N; that of the defender is 869 N. Immediately after the collision, Gretzky is moving at 2.21 m/s in his original direction. ...

Math
Find a third-degree polynomial Q such that Q(1)=0, Q'(1)=0, Q''(1)=2, and Q'''(1)=12.

Physics
An engine is used to pull a train of two cars out of a mine. The floor slopes upward at an angle of 24o. Each car has a mass of 0.8x104 Kg and normally travels without friction on the tracks. The engine can exert a maximum force of 1.4x105 N on car A. If the engineer again ...

Chemistry
N2H4(g) + H2(g) 2 NH3(g) H1 = –1876 kJ 3 H2(g) + N2(g) 2 NH3(g) H2 = –922 kJ The H f for the formation of hydrazine: 2 H2(g) + N2(g) N2H4(g) will be

science
what are 3 types of symbiosis

Physics
Thank you so much.

Physics
A 10,000N car comes to a bridge during a storm and finds the bridge washed out. The 650-N driver must get to the other side, so he decides to try leaping it with his car. The side the car is on is 16.6 m above the river, while the opposite side is a mere 7.90 m above the river...

english
in to kill a mocking bird who leaves their shoes at the school??? who does scout escort home?? whoes education does atticus help finance and who urges scout to stand up out of respect for atticus???

math
You can always dig up an extra player

math
a bathtub can be filled by the hot and cold water pipes in four minutes and, when full, can be emptied by the waste pipe in five minutes. If it is half full and all three pipes are set running, when will the tub be filled?

business studies
I was wondering could anyone help me with question 6 an page 302 of the Business Studies for households and enterprises Junior Certificate by Matt Hynes

CHEM
A 5.00 g sample of Al pellets (specific heat = .89 J/g degrees c) and a 10.00 g sample of Fe pellets (specific heat = .45 J/g degrees c) are heated to 100.0 degrees C. The mixture of hot Fe and Al is then dropped into 97.3 g of water at 22.0 degrees C. Calculate the final temp...

Chemistry
i don't even understand what the problem is asking.

CHEM
A 5.00 g sample of Al pellets (specific heat = .89 J/g degrees c) and a 10.00 g sample of Fe pellets (specific heat = .45 J/g degrees c) are heated to 100.0 degrees C. The mixture of hot Fe and Al is then dropped into 97.3 g of water at 22.0 degrees C. Calculate the final temp...

physics
why are the lengths of days in spring and autumn the same? if the sun does not set, why is it so cold?

One for Drwls (calc)
Thanks bob, and thanks to drwls too, in the earlier ones. Charlie.

One for Drwls (calc)
Sorry, you're so quick, I took one of your answers for another question! Finally, Therefore, given my scenario, I could use the integral to calculate the area under the curve described by the derivative? Charlie.

Calculus
Great, and thank you very much. Charlie.

Calculus
"My reasoning is that 'undoing' the derivative gives me the derivative." oops, meant to write ......gives me the integral.

Calculus
Thanks- that was quick! Therefore, given my scenario, I could use the integral to calculate the area under the curve described by the derivative? Charlie.

Calculus
If I have a function f(x), and am given its derivative, f'(x): may I take it as a given that f(x) is an integral of f'(x). My reasoning is that 'undoing' the derivative gives me the derivative. Eg is 1/3x^3 an integral of x^2? Thanks.

english
complete subject and simple subject of this sentence. Ties in fancy boxes are gifts for some valentines.

english
complete subject and simple subject of this sentence. They can be funny or serious.

english
whats another word for private? http://www.answers.com/private Scroll down and look for synonyms. =)

history
What caused the British government to take action with regard to the atrocities committed in the Congo by King Leopold's colonial managers in 1904? charlie, maggie, dali, or whoever, http://www.jiskha.com/search/search.cgi?query=atrocities Skip the first two links here, ...

history
Offer evidence to prove that the Congo Free State violated Articles I,V,and VI of the Berlin Act of 1885. Check this answer. http://www.jiskha.com/display.cgi?id=1186771696

Calculus:check please
given: 1st derivative is 2(2-3x-2x^2)/(1+x^2)^2 (quotient rule) I've found the stationary points to be x=1/2 and x=-2 Am I on the right track? If so, I plan to plug in values to the L andR of them into the whole derivative so as to clasify them. Still on track? Thanks ...

Graphing Functions
Can someone point me to a starting point in graphing f(x)= 25/cos x If it weren't a fraction and a cosine, I'd try to build a table of coordinates. This one, I have no start point. Thanks

science ( physics)
hello, i am having trouble with this problem. Calculate the average force of friction acting on a wood block as it is propelled along the floor by an elastic band ? my solution and my ideas: What does it mean by average froce of friction? I first weighed the peice of wood to ...

Physics please check
Answer is Counter Clock Wise

English
I wrote, "I like to swim in summer." My teacher marked it wrong and said it should read "I like to swim in THE summer." Can anyone offer an explanation, please, why my way is wrong? I don't know why it was marked wrong. Both with and without "the&...

biology/chemistry
Please help i am on a dead line and am stuck on this question, Gametes produced in the process of meiosis in humans (chromosome 4)has a long and short arm the short arm has the gene for Huntington's (H) attached and the long arm the gene for Red hair (R) i need to show (i...

One for drwls
Thank you for answering my question. Can you steer me to making a quadratic from 1/4(x+3)^2-4 Then I can get the intercepts. Thanks Just multiply it out to put it in the standard form, ax^2 + b^2 + c (1/4)(x+3)^2-4 = (1/4)(x^2 + 6x + 9) -4 = (1/4)x^2 + (3/2)x - 7/4 You're ...

Algebra
I'm trying this again, I'd like the quadratic form, so i can then work the intercepts myself. SO: what's the quadratic form of 1/4(x+3)^2-4 I need it to find the intercepts of the parabola it describes. Check: I think the parabola is 1/4 scaled, moved 3 to the left...

math
what's the quadratic form of 1/4(x+3)^2-4 I need it to find the intercepts of the parabola it describes. Check: I think the parabola is 1/4 scaled, moved 3 to the left and down 4 compared to a y=x^2 parabola. Is this ok? If you are looking for the intercepts, you will have...

egypt mummification
thx a lot....this saved me alot of time

PHYSICS HELP
It increases

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