Tuesday

November 24, 2015
Total # Posts: 414

**physics**

while watching ocean waves at the dock of the bay. otis notices that 10 waves pass beneath him in 30 seconds. he also notices that the crests of succesive waves exactly coincide with the posts that are 5 meters apart. what are the period frequency wavelength and speed of the ...
*February 11, 2011*

**physics**

the lowest frequency we can hear is about 20hz. calculate the wavelength associated with this frequency for sound that travels at 340m/s. how long is this in feet.
*February 11, 2011*

**physics**

calculate the speed of waves in a puddle that are 0.15m apart and made by tapping the water surface twice each second
*February 11, 2011*

**physics**

a nurse counts 76 beats in one minute. what are the period and frequency of the hearts oscillations?
*February 11, 2011*

**math**

In gift wrapping department, a customer can choose from x different papers, y different ribbons, and z different greeting cards. There are 160 different paper, ribbon, and greeting card combinations possible. List three of the possible combinations. What forumula are used? Don...
*February 2, 2011*

**math**

write the 100-complement of 40
*January 20, 2011*

**chemistry**

Lewis diagram for NO3- and NH4+
*January 10, 2011*

**physics**

calculate the period of a pendulum if the length of the pendulum is o.8m. what is the period if the angular deflection is 30 degrees? 45 degrees?
*January 8, 2011*

**physics**

calculate the amount of heat energy required to raise the temperature of a 5kg block of solid platinum from 0 degrees celsius to 25 degrees celsius. the specific heat of platinum is 133j/kg k. how much heat energy is required to raise 5kg of water by the same amount? the ...
*January 8, 2011*

**9th grade science**

A landslide may be caused when friction is ______ by moisture
*January 4, 2011*

**9th grade science**

A landslide may be caused when friction is ______ by moisture
*December 16, 2010*

**AP Physics**

A cylindrical container of radius 20 cm contains water of height of 3 m. Two meters down from the water level there is a hole of 0.5 cm in radius. Find the velocity and volume flow rate of water leaving the hole. Where does it strike the ground?
*November 29, 2010*

**math**

need help please. thanks evaluate and simplify. (8x/y) for x=10 and y=2
*November 14, 2010*

**math**

Tell which real number corresponds to the situation: During a month, a person withdraws $350. what is the corresponding # for this sentence?
*November 14, 2010*

**science-6th grade**

what is between the helium particles in a helium filled balloon?
*November 5, 2010*

**College Physics**

A mass of 0.4 kg, hanging from a spring with a spring constant of 80 N/m, is set into an up-and-down simple harmonic motion. What is the velocity of the mass when at its maximum displacement of 0.1 m?
*October 24, 2010*

**College Physics**

A multiple loop configuration is rotating at 60 Hz in a magnetic field of 0.12 T. The coil has an area of 0.0052 m2. How many coil loops are required to produce a maximum voltage difference of 170 V?
*October 24, 2010*

**Chemistry**

I conducted a simple titration experiment and i need to write how and why are the results reproducible can some one hlp me in answering this. Thankyou C.
*October 17, 2010*

**Science**

I have my results from a simple titration experiment (sodium carbonate against hydrochloric acid) Average titre of 53.27 cm3 which i am happy with but how can i reason that my results are accurate?
*October 15, 2010*

**Periodic Table **

Hello all, how does the periodic table determine the type of bonding of compounds Cheers Charlie.
*October 13, 2010*

**Science (Bonding)**

thankyou, srajmcgin
*October 13, 2010*

**Physics, relativity**

Thanks Drwls, but that's the press release I spotted the error in. I think!
*October 11, 2010*

**Physics, relativity**

I read this in a write-up of an experiment using atomic clocks: To reveal these effects, required the use of highly accurate atomic clocks, calibrated to check that they are perfectly in sync with each other – ticking down the nanoseconds (that's one billionth of a ...
*October 11, 2010*

**college chemistry**

whats is the boiling point of a solution composed of 17.6g of urea in (NH2)2CO in .300 kg of water
*October 4, 2010*

**physics**

the passenger's weight is ALWAYS mass x acceleration. Can you work out the acceleration at all 3 stages? The mass of the person is the same for all 3.
*September 28, 2010*

**11th grade**

Suppose you surveyed 50 students and 34 said that they approve of how the president is doing. Construct 90%, 95%, and 99% confidence intervals for the true proportion of students in your school who approve of how the president is doing. Be sure to specifically calculate the ...
*September 12, 2010*

**college physics**

A box on a frictionless horizontal surface is pulled by a tension of 42.4N directed at 45 degrees above the horizontal. what is the work done on the box as it moves 2.50 meters along the surface?
*September 11, 2010*

**college physics**

A box on a frictionless surface is pulled back a distance x into a spring with spring constant k and released. What is the formula for the kinetic energy of the box after it leaves the spring?
*September 11, 2010*

**College Physics**

A 50 kg skater moving at 5 m/s over frictionless ice grabs a rope stretched out 10m from a post and perpendicular to her path. She then moves in circles, spiraling inward as the rope wraps around the post. How fast is she moving when she is 2 meters from the post?
*September 11, 2010*

**8th grade Math**

3p - 1.5
*September 9, 2010*

**math**

let me retype the question. Sorry for the scribble. 1/2 X 1/2 answer in simplest form. must show work. thanks
*August 29, 2010*

**math**

desperately seeking help. work must be shown. answer must be in simplest form. Thanks 1 1 _ X _ 2 2
*August 29, 2010*

**mat115**

There are multiple choices for the answer to this problem. They are a) 1/5 b) undefined c) 5 d) 5/7 Thanks again for both of your help
*August 29, 2010*

**mat115**

Sorry Reiny, The question is 11-6/7-7 I thought the answer was 5/0= undefined. Can you please let me know if I am wrong and show the work so I can further understand your answer. Thanks Reiny
*August 29, 2010*

**Math**

Thanks Reiny, Yes, I spotted that it dosen't work for any run of primes, but it does up to 9. I'm afraid i don't really follow your explanation! An answer for dummies maybe? Charlie
*July 30, 2010*

**Math**

I have to find the relationship between these sequences, and express a generality. Could you help please. 1 + 3 + 5 + 3 + 1 = 3^2 + 2^2 1 + 3 + 5 + 7 + 9 + 7 + 5+ 3 + 1 = 5^2 + 4^2 1 + 3 + 1 = 2^2 + 1^2 I'm thinking sum of consecutive primes can be expressed in squares? ...
*July 30, 2010*

**Physics**

It's too hard. You should give up now
*July 6, 2010*

**gen.science**

A compound containing 3 atoms of carbon and 8 atoms of hydrogen is combined in a reaction with oxygen molecules. The two end products of this equation are carbon dioxide and water. Which chemical or element will have the largest number of moecules?
*June 21, 2010*

**chemistry**

What was the purpose of the phenolphthalein?
*June 1, 2010*

**Math algebra**

I'm reposting this, because Mathmate's answer hasn't directed me to the WHY? part of the question. Any prompts appreciated. The product of any two (whole) numbers each of which leave a remainder of 1 on dividing by 7, also leaves a remainder of 1 on dividing by 7...
*May 3, 2010*

**math**

I have this question to work on, and I don't know where to start investigating the answer: The product of any two (whole) numbers each of which leave a remainder of 1 on dividing by 7, also leaves a remainder of 1 on dividing by 7. Why? I THINK that I can see a quadratic ...
*May 2, 2010*

**physics**

If the angular quantities θ,ω,α were specified in terms of degrees rather than radians, how would the kinematics equations for uniformly accelerated rotational motion have to be altered?
*April 11, 2010*

**Physics**

Ok thanks, but why isn't this true for an arm or leg?
*February 3, 2010*

**Physics**

Why is the CM of a 1.00m length of pipe at its midpoint, whereas this is not true for your arm or leg?
*February 3, 2010*

**Math**

I need to figure out what a deposit of 3500 a month, with 9 percent intrest compounded monthly, would be in 6 years. Any help would be greatly appreciated.
*January 13, 2010*

**Math**

I need to figure out what a deposit of 3500 a month, with 9 percent intrest compounded monthly, would be in 6 years. Any help would be greatly appreciated.
*January 13, 2010*

**math**

-3/4
*January 13, 2010*

**freedom**

iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiissssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss WAR.
*January 11, 2010*

**Biology**

What differences would you expect to see in a population made up of individuals whose chromosomes experience crossing-over frequently compared with a population made up of individuals whose chromosomes do not cross over?
*January 6, 2010*

**algebra**

x+12+x-5+x=40 3x+7=40 3x=33 x=11 x-5+6 x+12=23 23, 11, 6
*December 16, 2009*

**AP Physics B**

can u give me these in numbers please, i dont understand what formulas u wrote and what some of the stuff in ur formulas are
*December 16, 2009*

**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
*December 16, 2009*

**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...
*December 16, 2009*

**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 ...
*December 8, 2009*

**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 ...
*December 7, 2009*

**Chemistry**

Thanks so much! I got 4.82 which seems to be correct. Thank you again
*December 7, 2009*

**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 ...
*December 7, 2009*

**Physical Science**

What is cracking and reforming? For what purposes are either or both used by the petroleum industry
*September 29, 2009*

**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.
*August 10, 2009*

**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
*August 10, 2009*

**english (help please)**

help
*August 2, 2009*

**english**

this is the quesion List four things to look for when you’re proofreading?
*August 2, 2009*

**english**

If you’re asked to list for things can the way of your listing be vertical or horizon.
*August 2, 2009*

**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...
*June 20, 2009*

**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 ...
*June 19, 2009*

**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...
*June 19, 2009*

**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. ...
*June 18, 2009*

**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 ...
*June 18, 2009*

**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 ...
*June 16, 2009*

**physics**

Thanks for that. So it would take longer to stop then?
*June 15, 2009*

**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 ...
*June 15, 2009*

**Physics/Maths**

Thanks
*June 11, 2009*

**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.
*June 11, 2009*

**Entropy**

Thanks for that.
*May 11, 2009*

**Entropy**

If a sample of an ideal gas is heated at a constant volume, I believe its entropy will increase. Am I right? Thanks.
*May 11, 2009*

**Physics capacitance**

Thank you very much.
*May 7, 2009*

**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.
*May 7, 2009*

**Thermodynamics**

Thank you for giving such a detailed answer.
*May 3, 2009*

**Thermodynamics**

Would someone explain entropy in simple terms please. Thanks.
*May 3, 2009*

**physics :thinking check please**

HELP! Time running out! Thanks
*April 30, 2009*

**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 ...
*April 30, 2009*

**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
*April 14, 2009*

**physics**

Thanks, CI
*April 11, 2009*

**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?
*April 11, 2009*

**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
*April 11, 2009*

**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
*March 30, 2009*

**math**

The answer was incorrect and that is why I am asking again Mr. Parsley
*March 27, 2009*

**math**

In the number 268,743 how many times greater than the 3 is the 6?
*March 27, 2009*

**math**

write the next four letters in this sequence A B Z Y C D
*March 27, 2009*

**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 ...
*March 27, 2009*

**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 ...
*March 27, 2009*

**math**

what is the answer to. Write the next 4 letters in this sequence: A,B,Z,Y,C,D
*March 26, 2009*

**math**

In the number 268,743 how many times greater than the 3 is the 6
*March 26, 2009*

**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
*March 24, 2009*

**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...
*March 24, 2009*

**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
*March 9, 2009*

**math**

the response from Ms writeacher did not show the answer
*March 9, 2009*

**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?
*March 9, 2009*

**math**

Thanks Jessica
*March 9, 2009*

**math**

what is the value of 4 in 0.045
*March 9, 2009*