# Posts by Zak

Total # Posts: 36

**Math**

A swimming pool is 25m long, 10m wide and 2m deep what is the volume

**math**

if 1 and 2/3 cups of flour make 20 pancakes how many will 1 cup of flour make?

**HELP HISTORY**

B C C D A A D B C B you're welcome

**Algebra 1**

A cashier has 25 bills consisting of twice as many ones as tens, two fewer fives than than ones, and the rest are twenties. If the total value is $140, find how many of each bill she has?

**chem**

Potassium-40 undergoes three different modes of radioactive decay (Beta decay, Positron decay, and Electron Capture decay). Write balanced nuclear reactions for each of these decay modes. Are the products stable (not radioactive)?

**physics**

KE 1= 1/2*0.002kg*300^2m/s=30 j KE2=0 work Tree=90 j f=ma first find a V2^2-V1^2 = 2AX - 300^2M/s = 2*a*0.05 A=900,000m/sec^2 f = 0.002*9e5 = 1800 newtons so this would be correct @mathmate ?

**chem**

19. A radioactive nucleus decays to yield a bismuth-211 nucleus and an alpha particle. What was the identity of the original nucleus? Show the nuclear equation that leads you to this answer.

**physics**

in passing theough a wooden block 8cm thick the velocity of a beullet reduces from 700m/s to 300 m/s if the mass of the bullet is 10g find the average resitance to penetrate ?

**chemistry**

What amount of current, in amperes, would be required to deposit 19.7 g of Au metal in 1.00 hour from a solution of Au(NO3)3?

**math**

125

**chemistry**

i have some question but i can not post it ,what should i do .help

**chem**

how many moles of Na are there in 1.50 moles of NaCl ?

**chemistry help**

sulfuric acid is a strong acid and dissociates in water as shown in reaction H2SO4(aq)=2H^+(aq)+SO4^2-(aq) what is the hydrogen ion concentration, in mol dm^-3,when 1.50g of sulfuric acid is dissolved in water to give 0.500dm^3 of solution ?show all of your working and give ...

**PHISIC help**

A bouncy rubber ball is dropped from a height of about a metre above the ground .it falls to the ground, bounces and then rises back to almost the height from which it was dropped. Describe the main energy transformations that take place from the point at which the ball first ...

**Science need help**

Astronomers believe that the biggest stars in the Galaxy may be a hundred times more massive than the Sun, but are a million times brighter. Would you expect such stars to have longer, shorter or comparable lifetimes to that of the Sun?

**Math**

It's right because 5x5x5=125 and 125x2=250

**Measurement**

Can anayone tell me something that is 65 mm long or wide?

**Calculus**

1. Does the limit limx-->0:6[[x]] exist? 2. Does the limit limx-->3[[x]] exist? [[x]] is less or equal to x.

**chem**

What is the entropy change to the surroundings when 1 mol of ice melts in someone’s hand if the hand temperature is 32°C? Assume a final temperature for the water of 0°C. The heat of fusion of ice is 6.01 kJ/mol. a. –188 J/K d. b. –22.0 J/K c. –19.7...

**CHEMISTRY**

What is the entropy change to the surroundings when 1 mol of ice melts in someone’s hand if the hand temperature is 32°C? Assume a final temperature for the water of 0°C. The heat of fusion of ice is 6.01 kJ/mol. a. –188 J/K d. +19.7 J/K b. –22.0 J/K e...

**Chemistry**

If 1 mol of ice melts at its melting point of 273 K, the entropy change for the ice is 22.0 J/K. If the ice melts in someone’s hand at 34°C, what is the change in the entropy of the universe? Assume a final temperature for the water of 0°C. The enthalpy of fusion ...

**Calculus urgent help**

evaluate the limit as x approaches infinity for the absolute value of (the square root of xsquared+x) -x i think the answer is 1/2 from my calculator but I have to show how i got it algebricallly and have no clue what to do

**chemistry**

it is a method of which you use to do scientific projects and stuff. its the order in which you write the information.im not exactly sure of the order though

**Math**

Paul is 12. His father is 33. How many years ago was the father 4 times as old as the son?

**Physical Science**

11. Chromium is produced by reacting its oxide with aluminum. If 76g of Cr2O3 and 27g of Al completely react to form 51g of Al2O3, how many grams of Cr are formed?

**social studies: geography**

What feature makes up part of the U.S border with Canada? What feature makes up much of the U.S border with Mexico?

**socialstudies**

what conditions drew people to the tigris-euphrates vally

**AP Calc**

Hi, I have few problems that I really need help solving. I think I start out right but get messed up along the way and get the wrong answer...Any help is appreciated! thank you so much! find derivative of: 1) y=arctan 2^x 2) arctan(xy)= 1+x^2y Also... 3) find the equation of ...

**calculus**

Ohhh, I get it!! Thanks so much, you helped me a lot! :)

**calculus**

Question: "Plutonium isotope Pu-239 has a half-life of 24,100 years. Suppose that 10 grams of Pu-239 was released in the Chernobyl nuclear accident. How long will it take for the 10 grams to decay to 1 gram?" I know that I am suppose to use y= ye^kt , to get the ...

**spanish**

hi, I'm having trouble differenciating between direct object pronouns and indirect object pronouns. To say: "bears scare me" is that direct object pronoun? So it would be "los osos me asustan"? To say: "they(bears) scare them" is that still ...

**economics**

I have an assignment where I am suppose to find any recent situation that shows how the Eurpean union (or european nations) are in touble of credit crunch. I'm not quite sure what credit crunch is and how the EU is suffering through (or did?) one recently. Can you please ...

**history**

what are three important US domestic politics(domestic events/issues) from the 1990s? I have been searching for the answer, but I keep on only finding foreign politics and not domestic ones and the domestic issues I do find are not from 1990s...someone please help me!!

**environmental science**

what is the range of tolerance of physical and chemical conditions for giant pandas?

**history**

what does popular consent mean???

**civilizations**

Out of all the different civilizations, which one is the least known ? Since you're asking about the "least known" civilization, there aren't going to be many (if any) answers -- since people don't know about it! If you search Google for "little ...

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