Friday
April 25, 2014

Posts by Charlie


Total # Posts: 364

AP Physics B
i figured out the amplitude and the period, i just dont kno how to get to the other 4 with using simple harmonic motion equations

AP Physics B
The position of a 20 g oscillating mass is given by x(t) = (2.0 cm) cos(2t), where t is in seconds. Determine the following. The Amplitude (cm.) The Period (s.) The Spring Constant (N/m) The maximum speed (cm/s) The total energy (J) The velocity at t=0.40 s. (cm/s) I need your...

Chemistry
The titration of 25.0 mL of an unknown concentration H2SO4 solution requires 83.6 mL of 0.12 M LiOH solution. What is the concentration of the H2SO4 solution (in M)? A) 0.40 M B) 0.10 M C) 0.20 M D) 0.25 M E) 0.36 M The answer is supposedly C, but I got A. What am I doing wron...

Chemistry
Uranium-235 can be separated from U-238 by fluorinating the uranium to form UF6 (which is a gas) and then taking advantage of the different rates of effusion and diffusion for compounds containing the two isotopes. Calculate the ratio of effusion rates for 238UF6 and 235UF6 Th...

Chemistry
Thanks so much! I got 4.82 which seems to be correct. Thank you again

Chemistry
Consider the following reaction: 2NiO (s)--> 2Ni(s) + 2O2 (g) If O2 is collected over water at 40.0 C and a total pressure of 752 mmHg, what volume of gas will be collected for the complete reaction of 25.67 g of NiO? I am struggling to set up this problem. Can anyone help ...

Physical Science
What is cracking and reforming? For what purposes are either or both used by the petroleum industry

Physics
I'm not doing the measuring, it's a graphing exercise, and I've been given the table of data. I was looking for confirmation of my choice of axes. But your extra points are well taken. Thanks for your comment.

Physics
I have to plot a graph of Pressure gradient vs average velocity (water in a pipe, I have all the data). I plan to put the average velocity on the x axis, since I could control that better in an experiment. Do you agree/ Thanks. Charlie

english (help please)
help

english
this is the quesion List four things to look for when you’re proofreading?

english
If you’re asked to list for things can the way of your listing be vertical or horizon.

Physics
Would someone check this please? A circular loop of wire of radius 0.10 m and of resistance 2.0 x 10^−3 ohms is in a region where there is a uniform magnetic field B. The field is at 30deg to the normal to the plane of the wire loop as shown in Figure 3. The magnitude of...

physics
The last stage in the fusion of hydrogen to form helium in the Sun involves the formation of an alpha particle (4He) from two 3He nuclei: 3He + 3He 4He + p + p The binding energy for 3He is 2.57 MeV per nucleon and that for 4He is 7.07 MeV per nucleon. Calculate the amount of ...

Physics
Would someone check this please? A circular loop of wire of radius 0.10 m and of resistance 2.0 x 10^−3 ohms is in a region where there is a uniform magnetic field B. The field is at 30deg to the normal to the plane of the wire loop as shown in Figure 3. The magnitude of...

Physics
The last stage in the fusion of hydrogen to form helium in the Sun involves the formation of an ƒ¿-particle (4He) from two 3He nuclei: 3He + 3He ¨ 4He + p + p The binding energy for 3He is 2.57 MeV per nucleon and that for 4He is 7.07 MeV per nucleon. Cal...

Physics
Would someone check this please? A circular loop of wire of radius 0.10 m and of resistance 2.0 ~ 10−3 ƒ¶ is in a region where there is a uniform magnetic field B. The field is at 30‹ to the normal to the plane of the wire loop as shown in Figu...

Physics
In an elastic collision: mass a is 1kg, and is moving at 100ms^1 in the +ve x direction when it hits mass b, 10kgs at rest. Given: mass a moves off at 80 ms^1 in the -ve x direction. What's the final velocity of mass b. Using cons of momentum, i say 2 ms^1 in the +ve x dir...

physics
Thanks for that. So it would take longer to stop then?

physics
Would someone check my thinking please. A solid sphere (mass, r, and moment of inertia given) is rotating at a given angular speed. Friction is constantly applied at the 'equator' of the sphere, and brings it to rest in 3s. Find the force. I worked out the torque, and ...

Physics/Maths
Thanks

Physics/Maths
Keplers third law I understand. T^2/a^3 of one planet = T^2/a^3 second planet. But I can't do the algebra to solve for the second planet's a^3 (semimajor axis) Would someone walk me through the steps please? Thanks.

Entropy
Thanks for that.

Entropy
If a sample of an ideal gas is heated at a constant volume, I believe its entropy will increase. Am I right? Thanks.

Physics capacitance
Thank you very much.

Physics capacitance
I know that to solve: f=1 over 2 pi sqrt LC for C, I have to use C= 1 over L(2 pi f)^2 Can someone take me through the rearranging please. Thanks.

Thermodynamics
Thank you for giving such a detailed answer.

Thermodynamics
Would someone explain entropy in simple terms please. Thanks.

physics :thinking check please
HELP! Time running out! Thanks

physics :thinking check please
I think that: psi= A sin kx; is a solution to Schrodinger's time independent eqn for a particle confined: a) within an infinite pot well, and b) within the walls of a finite well;but psi= B exp(-kx) would only be a solution for outside the walls of a finite well. Am I clos...

Physics
If energy is 1/2 mv^2; and m and v are always positive.... How come the ground state energy of Hydrogen is a minus value? Charlie

physics
Thanks, CI

physics
If I had made it conditional that the electron was orbiting at a constant radius, would it then be correct; and would it also be accurate in 'ordinary' situations, eg spinning a stone around on a string?

physics
I've just read that the centripetal force on an electron is mv^2/r; and that this is also equal to the electrostatic force pulling the electron toward the nucleus. Does mv^2/r hold good in all Newtonian siuations as a formula for centripetal force acting on a body? Thanks

physics: relativity
I think I can rearrange the Lorentz contraction equation, solving for v using: v=sqrt[1-(L/Lo)^2] x c^2 Would someone check my thinking please? Thanks

math
The answer was incorrect and that is why I am asking again Mr. Parsley

math
In the number 268,743 how many times greater than the 3 is the 6?

math
write the next four letters in this sequence A B Z Y C D

Physics
Reposted under Physics... I've tried for hours to solve for v, but can't get the rearranging right. I'm using L= Lo sqrt 1- v^2/c^2 Can anyone suggest the first couple of steps? I can get the answer by the way, by substituting values 'til I get the contracted l...

lorentz contraction
I've tried for hours to solve for v, but can't get the rearranging right. I'm using L= Lo sqrt 1- v^2/c^2 Can anyone suggest the first couple of steps? I can get the answer by the way, by substituting values 'til I get the contracted length. Original and final ...

math
what is the answer to. Write the next 4 letters in this sequence: A,B,Z,Y,C,D

math
In the number 268,743 how many times greater than the 3 is the 6

lenses, still stuck!
Thanks drwls, for that. However, the question acually asks me 2 things: the total M; and to find the length of the microscope! The questioner clearly thinks I have enough info to go on from what I've given above. Charlie

lenses, still stuck!
I need to calculate the magnification, m of an objective lens, so I can then x it by the eyepiece value for M to get the total magnification. I need v/u (v is dist from lens to image; u is dist of object to lens) I'm using 1/f = 1/v+1/u rearranged for 1/v. That's: 1/v ...

math
Ms Writeacher my math work book which is a fifth grader Harcourt Math Practice Workbook does not say what Tues so my mon think it has to be the same Tues in the week of the other days

math
the response from Ms writeacher did not show the answer

problem solving
kirk grew a crystal in science class. On monday it was 13/16 inch tall. it had grown 1/4 inch bet friday and monday. It had grown 1/2 inch between Tues and Fri. How tall was Kirk'a crystal on Tues?

math
Thanks Jessica

math
what is the value of 4 in 0.045

Physics
Can the magnitude of a magnetic field be negative? If we consider an electron in a mag field, using r=mv/qB, the negative charge on the electron gives a negative answer. Do I drop the minus sign?

Math/Physics
In a 9V circuit, all the resistors are 20 or 40 kilo Ohms. Convention says that calcs should therefore be quoted to 1 sig fig, since the volts are the least accuracy. 2 seems better though. Any ideas?

Sig Figs
In a 9V circuit, all the resistors are 20 or 40 kilo Ohms. Convention says that calcs should therefore be quoted to 1 sig fig, since the volts are the least accuracy. 2 seems better though. Any ideas?

Physics
Thanks (I'm not much wiser!), but what's ve as in 'between ve and zero' please?

Physics
(1) 2 particles of equal mass are fixed at X=0 and another +ve point on the x axis. No other grav influences are in the system. (they can be ignored) I have to derive an expression for Vgrav at a general position x, on the x axis. I believe this is related to V=-GM/r, but can&...

gravitational potential
(1) 2 particles of equal mass are fixed at X=0 and another +ve point on the x axis. No other grav influences are in the system. (they can be ignored) I have to derive an expression for Vgrav at a general position x, on the x axis. I believe this is related to V=-GM/r, but can&...

biology
can i get some help here please? much appreciated.

biology
i'm doing the same problem and confused about the same thing, so i'll just wait for the answer

Physics, Thinking check please
Very kind drwls, thanks a lot. Charlie

Physics, Thinking check please
A 9v circuit charges a capacitor to steady state. Then the switch is opened. All resistance units in kilo-ohms: 2 rsistors, 20 and 40kO in parallel with a single 20 kO resistor. Total R is 3.33x10^4 Ohms. Am I close? If so, and the time constant is 1.6x10^-3 seconds, then is t...

physics: Electricity/Resistance
I forgot to say "take the reciprocal". Does that make more sense?

physics: Electricity/Resistance
I get it. My text shows your formula, but recommends 1/R= 1/R1+1/R2 etc as easier! I'm with you. If the numbers match, is my thinking ok?

physics: Electricity/Resistance
If I have a 9V circuit, with: 2 resistors in parallel; followed by: 2 single resistors in series; and I calculate the effective R of the parallel pair (using 1/R=1/R1+1/R2); can i then add this value to the series resistors to get a total for the circuit? As in: (1/R=1/R1+1/R2...

Physics
that's 3x10^6, not -6

Physics
I need to calculate the closest two parallel plates can get before they spark I have the voltage, and will use E=V/dist (rearranged) to get the distance. I THINK the field strength value I should use is 3x10^-6 Vm^-1. No other info is given in the question, so am i close? Thanks

Physics
I'm stumped: So bringing it back to the top. Hope that's ok! 2 charges, Q1 and Q2, equal magnitude, but different signs (not assigned) lie on a line, x axis, a known distance apart. Segment p-q lies centrally on the line, distance apart is known. An electron is release...

physics fields and charges
Sorry, the field is said to be constant around the central segment pq, which is only 10 cm long.

physics fields and charges
I'm stumped: 2 charges, Q1 and Q2, equal magnitude, but different signs (not assigned) lie on a line, x axis, a known distance apart. Segment pq lies centrally on the line, distance apart is known. An electron is released at p from rest, and passes q at a given time later....

physics, fluids
Thanks, all 3.

physics, fluids
It's given that it is an ideal fluid, and I'm asked to explain the significance of the expressions. I se a relationship with 1/2mv squared and mgh, but can't explain it clearly.

physics, fluids
would I be correct if I explained the 3 expressions in Bernoulli's equation as representing: P is the pressure 1/2*rho*v squared is the kinetic energy rho*g*h is the gravitational kinetic energy. Or is it more complicate than that. Thanks

Human Anatomy
What are the bony landmarks of the abdominopelvic cavity?

French
My french teacher has asked us too gather us questions to ask our pen pals on a live link up. (webcam to each other) but, i cannot think of anything to ask her. Please help and give me some ideas ? Charlie. x (:

Atomic Mass
Hi if I divide a molar mass of an element by Avogadro's number (63022X10^23) will i have the mass of 1 atom of the element? Thanks

physics
Spotted! Thanks Dr Bob.

physics
Hi if I divide a molar mass of an element by Avogadro's number (63022X10^23) will i have the mass of 1 atom of the element? Thanks

Physics ideal gases
Thank you both.

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 rem...

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 t...

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 t...

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 velocit...

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 pl...

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 pl...

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 pha...

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

Pages: <<Prev | 1 | 2 | 3 | 4 | Next>>

Search
Members