Tuesday

February 21, 2017
Total # Posts: 438

**Physics**

When an electron makes a transition from its first quantum level to ground level, the energy difference is carried by the emitted photon. In comparison, how much energy is needed to return an electron at ground level to the first quantumlevel?

*April 10, 2008*

**Physics**

Uranium-238 is 238 times more massive than hydrogen. Why, then, isn't the diameter of the uranium atom 238 times that of the hydrogen atom?

*April 10, 2008*

**Physics**

How does Rutherford's model of the atom account for the back-scattering of alpha particles directed at the gold foil?

*April 10, 2008*

**Physics**

Which color light is the result of a greater energy transition, red or blue?

*April 10, 2008*

**Math(Easy Survey Please Help)**

1. Do you exercise or work out on a regular basis? no 2. Are you male or female? female 3. Do you smoke? no 4. How many carbonated soft drinks do you consume in a week. none 5. Do you drink coffee. occasionally 6. How many servings of fruit, or fruit juice do you consume in a ...

*March 22, 2008*

**French**

Well, my opinion isn't expert, but it sounds like a misprint. It should just be "des" both times because the particle "des" is of course "the" and should only apply to the plurality of the word "numbers"

*March 22, 2008*

**Physics (Mechanics)**

A uniform plate of height H= 0.69 m is cut in the form of a parabolic section. The lower boundary of the plate is defined by: y= 1.10x^2. The plate has a mass of 5.62 kg. Find the moment of inertia of the plate about the y-axis. Alright, I've done this so far: So I figured...

*March 21, 2008*

**Physics**

Alright, so what you are looking at is a conservation of energy problem. Total Mechanical Energy in a system where energy is conserved is always equal to the sum of the kinetic energy and the potential energy. The sum of the change in these two quantities is also equal to zero...

*March 21, 2008*

**math**

thank you

*January 30, 2008*

**math**

A rectangle has sides of 4x – 4 and 8x + 10. Find the expression that represents its perimeter

*January 30, 2008*

**math**

The sum of two numbers is 38. Their difference is 12. What are the two numbers?

*January 25, 2008*

**Math**

thank you so much

*January 24, 2008*

**Math**

The difference of two numbers(the second minus the first) is 48. The second is 8 less than 5 times the first. What are the two numbers?

*January 24, 2008*

**math please help**

The length of a rectangle is 8 in. more than twice its width. If the perimeter of the rectangle is 34 in., find the width of the rectangle.is it 1. 2 in. 2. 3 in. 3. 4 in. 4. 5 in.

*January 24, 2008*

**math**

can someone hep me please Population of Europe by Age Groups Population (in thousands) 1----------1950 --1970 --1995 Age 0-14--------143,175 166,367 139,464 Age15-64------- 359,162 421,432 487,110 Age 65+ 44,981- 68,642- 101,338 Age 75+ 14,553- 22,762- 38,139 Total--547,318 ...

*January 11, 2008*

**math**

can someone hep me please Use the following tabe to answer the question. Population of Europe by Age Groups Population (in thousands) 1----------1950 1970 1995 Age 0-14 143,175 166,367 139,464 Age15-64 359,162 421,432 487,110 Age 65+ 44,981 68,642 101,338 Age 75+ 14,553 22,762...

*January 11, 2008*

**math**

can someone hep me please Use the following tabe to answer the question. Population of Europe by Age Groups Population (in thousands) 1950 1970 1995 Age 0-14 143,175 166,367 139,464 Age15-64 359,162 421,432 487,110 Age 65+ 44,981 68,642 101,338 Age 75+ 14,553 22,762 38,139 ...

*January 11, 2008*

**math**

so it would be a and d

*January 11, 2008*

**math**

purple- 1 in 63 brown- 1 in 62

*January 10, 2008*

**Algebra 1**

explain: 3x-y=12 4x-5y=16 it is linear equations using substitution method

*January 10, 2008*

**Algebra**

Thank You, I am just making sure before I turn this in.

*September 6, 2007*

**Algebra**

Would this be correct? Factpr completley: y^3-12y^2+36y y(y^2-12y+36) y(y-6)^2

*September 6, 2007*

**Algebra**

I am wondering if I did this right? Write Using a positive exponets and simplify if possiable. (-3x)^2 I took the -3^2=9 over the x^2 and the answer would be - 9 over x^2

*September 6, 2007*

**Algebra**

I do not understand what I am supposed to do: The problems reads: Evaluate (assume x is not equal to 0). -10x^0 I did this though not sure about it, -10*x^0 -10*1 -10

*September 6, 2007*

**algebra**

I would say.... Mona, Jack, Pete, Nick

*August 30, 2007*

**Algebra**

Ohh, I knew something looked off...so it should be x^2-5x/80-9/20

*August 29, 2007*

**Algebra**

know I am supposed to use the FOIL method.But is this right? I am really not sure I did this right, something just seems off about it. So i would Multiply x/3 * 3x/4=x^2/4 x/3 *-3/5= -x/5 3/4 *3x/4=9x/4 3/4 * -3/5 I know to add both of my bottom numbers have to be the same so...

*August 29, 2007*

**Algebra**

How do you Multiply this? (x/3+3/4)(3x/4-3/5)

*August 29, 2007*

**History**

. Describe the three key concerns that Washington had for the future of the U.S. Explain how the country has progresses in each area and give one specific example. Here's an answer I posted for this question a few days ago. http://www.jiskha.com/display.cgi?id=1187480916

*August 21, 2007*

**Chemical Kinetics**

When experimentally determining the rate law, i am getting a negative fraction. is that right or am i doing something wrong? It is possibly right. I'd have to see you calculations to determine that. It would mean that the reaction is proceeding backwards.

*March 7, 2007*

**science**

Does salt water evaporate faster than fresh water? No. The reduction in vapor pressure and evaporaton rate is related to the fraction of the surface that is salt ions instead of water molecules. The Na+ and Cl- ions are not volatile.

*February 15, 2007*

**Biochem**

Can someone please help me find, or know of any molecules that are at least 20 bases (carbons, nitrogens..) long and have 3 hybrids (sp, sp2, dsp)

*December 28, 2006*

**Probability**

You throw a beanbag at a wall with 7 colored squares, each with an area of 1/4^2. If you hit a square, you win a prize. What is the probability of winning a prize? You need more information. For starters: 1) what is the total area of the wall? 2) Are landings on the wall ...

*December 5, 2006*

**Social studies.. need help**

What did the peolpe in Jamestown eat? Jamestown is where John Smith lived... Thankssss http://www.apva.org/exhibit/eats.html THANKSSSS!!!!!!!!!!!!!!!!!!!! LANCEEEEEEE!!!!!!!!!!!!!!

*November 21, 2006*

**social studies**

the answer is NOT linen.NOT dimainds.The correct answer IS BEESWAX!!!

*November 16, 2006*

**lane**

Changes in size or shape occur what? This depends on what you are writing about. For doughnuts, changes in size or shape occur rarely, but for an expectant mom, they change daily. You'll need to be more specific in your question. It would also help if you put the SUBJECT (...

*November 8, 2006*

**Business**

I need at least two or three examples as to how outsourcing project work can help alleviate some of the common problems associated with multiproject resource scheduling. Any help will be appreciated. This is the only part of the entire assignment that is left. Thank you :o) ...

*October 19, 2006*

**Business**

I need at least two or three examples as to how outsourcing project work can help alleviate some of the common problems associated with multiproject resource scheduling. Any help will be appreciated. This is the only part of the entire assignment that is left. Thank you :o)

*October 19, 2006*