# Posts by PC

Total # Posts: 44

**Physics**

What is the total kinetic energy if a 0.30 kg block is sliding on a smooth horizontal surface at 2.5 m/s, heading towards a light spring that is in equilibrium?

**Physics**

What is the total kinetic energy if a 0.30 kg block is sliding on a smooth horizontal surface at 2.5 m/s, heading towards a light spring that is in equilibrium?

**Math**

One saved about $300 . If one how many seasons to the nearest 100 which could not be there as the mount of money saved? $167 $198 $225 $251

**trig**

John weighed five rocks two at a time in all possible ways. The weights in pound are 30,38,41,42,45,46,50,53,58,61. How much does each rock weigh?

**Cal**

The sum of two logarithms is equal to the logarithm of the product, and the difference equals the quotient: log(A)+log(B)-log(C) =log(AB/C) Twice the logarithm of a quantity is the logarithm of the square of the quantity: 2log(C)=log(C²) So if we put it all together, we ...

**Foreighn Languages**

Learning both will give you a chance to have a first hand knowledge of which one suits you better. Also, you may want to consider which one might help you in your future career/travels.

**MATH**

Ways to get a sum of six =|{(1,5),(2,4),(4,2),(5,1)}| = 4 ways given that doubles are not rolled, therefore (3,3) was absent. Total number of ways: 6 faces * (6-1) faces to eliminate doubles = 30 So probability of rolling a total of 6 = P(6) = ?

**physics**

What is 109 grams/ 123 ml. ?

**maths (trigonometry)**

Multiply both numerator and denominator by the conjugate, (1+sin(a)-cos(a)) To reduce typing, will use s=sin(a), c=cos(a), so (1+sin(a)- cos(a))/(1+sin(a)+cos(a)) =(1+s-c)/(1+s+c) =(1+s-c)²/((1+s+c)(1+s-c)) =(1+s²+2s+c²-2c(1+s))/((1+s)²-c²) now use s&...

**IT computer memory**

You have to double check the question: "18 MB of data are to be transmitted over a a megabyte per second connection" Is it "a" megabyte connection" or is it "4 megabit connection"?

**Math**

area on map = actual area / scale^2 = 124 km^2 / 20000^2 = 124 (1000m)^2 / (20,000)^2 = 124 / 400 m^2 =0.31 m^2

**electrical and electronic engineering**

investigate the impact of photovoltaic system on low voltage distribution network in Malaysia.

**test**

Thanks!!!

**Chemistry**

Oops, thanks Dr. Bob.

**Chemistry**

Can you start with finding the weight of the tin foil? Tin (IV) means that the resulting compound is Sn++++, or equivalent meaning: Sn + 2O2 = SnO4 With the ATOMIC mass of tin=118.17, and 16 for O2, you should be able to complete the calculations.

**chemistry**

Excellent, Kate!

**chemistry**

Kate, You'd have to read the graph, but concentrate on the line that says KCl. The x-axis represents the temperature, and the y-axis represents the maximum number of grams of solute (KCl) that dissolves in water. This value represents the saturation point. Any solution ...

**chemistry**

If you google "potassium chloride Wiki", you will find somewhere the solubility of KCl as 34.4 g/100 ml. of water at 20 degrees C. Refering to your previous question on saturated solution, you will find a definition of solubility, you should be able to tell if 20 g ...

**physics**

I have uploaded a graph but I am unable to show the link as I do not have privileges to do so. Sorry.

**physics**

physics - PC, Friday, May 29, 2009 at 12:18am Here is a copy of the previous response. > (0,0), (1,1), (2,2.5), (3,5), (4,7) Could you check the data for the blue ball to see if it is not: (0,0), (1,1), (2,2.5), **(3,4.5)**, (4,7) If that's the case, you will find that ...

**physics**

Sam, The response to "physics - sam, Thursday, May 28, 2009 at 11:43pm" had been posted last night, even with a suggested correction that you have made this morning. Would you like to check back before we continue?

**algebra**

I assume you want the given expression factorized. First take out the common factor of -3 in all the terms to get -21x^2 +6x-12 =-3(7x^2-2*x+4) Then see if you can factorize the expression in brackets. If not, the result will be as shown above.

**physics**

> (0,0), (1,1), (2,2.5), (3,5), (4,7) Could you check the data for the blue ball to see if it is not: (0,0), (1,1), (2,2.5), **(3,4.5)**, (4,7) If that's the case, you will find that the function of the blue ball is y=f(x)=(x^2+3x)/4 in which case you can easily solve ...

**Mrs. SUe**

Sarah, Your compliments and appreciation are worth more than a paycheck for those of us who help out here. PC

**chemistry help**

Unfortunately this is not the intended answer. Could you please show how you got 411 grams?

**chemistry help**

The solubility of a solute (ammonium chloride) in a solvent (water) is the maximum mass of the solute that can dissolve in 100 ml. of solvent at the given temperature. The solubility of ammonium chloride in water at 20 degrees C is 37.2 g. according to Wikipedia, under ...

**math**

Your answer tells me that you are in the right direction, but there is something wrong with the expression: (0.4x0.12)/(0.4x0.12)(0.18x0.6) because it evaluates to 9.259 > 1. Think of a bag of 4 red and 6 blue marbles. The chances of drawing a red would be 4/(4+6)=0.4. ...

**math**

For the identity to be true, the values inside the log functions have to be greater than zero. Try sketching the function x^2+5x+6 in the x-y plane, you will see that the value of the function is greater than zero when x>-2 and x<-3. Now repeat the same for x+2 and x+3. ...

**organic chem/ melting pt lab**

In general, a tighter packed crystal lattice of a solid will have a higher melting point. Impurities tend to disrupt the crystal lattice, so they always lower the melting point to a certain limit, which is called the eutectic point. The blend is called a eutectic mixture. When...

**French**

"Une chemise" is a shirt. "Un chemisier" is a shirt-maker. Do you happen to have a dictionary? It indicates the gender as m (masculine) and f (feminine). For example, if you look up "chemise", you will see: chemise n. f.(n=nom, f=feminin) ...

**French**

Oops, sorry Angie. There was a typo in my answer, but Sra has given the correct answer. Hope that didn't confuse you. The corrected line should read: "meilleure should be written meilleur."

**French**

If you are not allowed to change the sentence, then the problem is what you stated: qu'un has been misspelled as q'un and meilleure should be written meilleure. I would prefer to say: Une note "A" est meilleure qu'une note "F". Here meilleure is...

**Geometry**

I believe you have posted this question before. The reason you may not have got an answer, as far as I am concerned, is that the question is not complete. Perhaps your teacher did not provide the information because it was obvious for him. For anyone to be able to calculate/...

**algebra**

1. 5x^2-x You can find the roots to an equation (which always has an equal sign) or you can (or cannot) factorize a polynomial. Since the expression is a polynomial, you can certainly factorize it. Look for common symbols as a first step. 2. x^2-15x+56 These are relative easy ...

**algebra**

1. -4x^2 and x^3 + 2x^2 - 5x + 3... you can multiply term by term to get the results. 2. x^2 + 30x = 1000 see answer for Fishboy who posted the same question after you. 3. 6x^2 - 2x -20 Look for the obvious common factor 2 in each of the terms. This reduces to 2(x^2-x-20) Now ...

**french**

Sorry, there was a problem with encoding. The sentence should have read: "Allez tout droit, prenez la troisième rue à droite",

**french**

If you say "Allez tout droit, prenez la troisiÃ¨me rue Ã droite", you are giving directions to someone driving (or walking) to "Go straight ahead, turn right on the third intersection". Notice that "tout droit" means ...

**Chemistry**

What do you think about the temperatures of the air in the balloons? Are they the same or different? If they are different, what effect do you think the temperatures would have on the volumes?

**Chemistry**

The answer will also explain why we don't see compounds of that element in the chemistry lab. Unstable isotopes are radioactive!

**Chemistry**

The elements mentioned on the list have 0,1,2 and 4 stable isotopes, but NOT in order. You only have to browse through articles on stable isotopes to find out which one you need. For example, Google "stable isotope", the Wiki article provides a complete list.

**math**

> a wheelchair ramp has a slope of 1/10 means that it rises 1 foot (rise) over a horizontal distance (run) of 10 feet. Slopes are measured by the ratio rise/run. For example, a rampe of 1/17, which is ususally the maximum preferred slope to enable manual wheelchairs to ...

**math b**

A median is a line joining the a vertex to the mid-point of the opposite side. If the median is also an altitude to side BC, then the median should be perpendicular to BC. Let D be the mid-point of BC. The coordinates of D should be rather obvious, being the mid-point of ...

**Math**

The simplest way to determine if inverse f(-x) =-inverse f(x) is true for all values of x is to find out if f(x)=f(-x) for all values of x. Substitute sin(x) or cos(x) for f(x) above and do a little sketching of each of the two trigonometric functions between -pi and +pi. You ...

**Math**

If you put the cost of a marker as x, and the cost of a pencil is y, then 3x+2y=? and if you do the same for the second part of the question, you will end up with two equations with two unknowns from which you should be able to solve for x and y.

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