 # janaki

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17

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Quark
• Birthday 03/08/1991

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http://www.eurekasparks.ga

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India
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8
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sleeping
• Biography
Medicine
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Doctor, MBBS
1. ## Expression for Electric ptential energy for System of n' charges

Thanks all.. - swapna
2. ## Expression for Electric ptential energy for System of n' charges

Thankas all, How to find U?
3. ## Expression for Electric ptential energy for System of n' charges

How to Derive an Expression for Electric ptential energy for System of n' charges?
4. ## Calculate the [H+] in each of the following solution?

thanks
5. ## When a 1.25-gram sample of limestone CaCO3 was dissolved in hydrochloric acid, 0.44 gram of CO2 was generated.?

If the rock contained no carbonate other than CaCO3, what was the percent of CaCO3 by mass in the limestone? CaCO3 + 2HCl ----> CaCl2 + CO2 + H2O
6. ## Calculate the [H+] in each of the following solution?

[OH - ] = 5.97 X 10e-8 M wouldn't [H+] = 5.97 X 10e-6?
7. A student determined the density of an unknown solid metal. He partly filled a pre-massed flask of known volume with solid and found the mass. Keeping the metal in place he then added water to fill the remaining volume of the flask. He used his data and correct calculations to find out the metal had a density of 6.95g/mL. The teacher let him know that the actual density of the metal was 7.86g/mL. For each of the following, indicate if this would be a valid explanation for the difference in the experimental and actual density. a. The irregular shape of the metal pieces caused air pockets to be trapped between those spaces. b. The metal was wet when it was first placed in the empty flask. c. The student assumed the water temperature was 20C (d=0.9982g/mL) but it was actually warm water, 30C (0.9956g/mL)
8. 36 / 6(2+2+2) = ?? What is the right answer?? 1 or 32 ?? My friend told me, "use BODMAS.. ==> 36/6*6 ==> 6*6= 36 "
9. a stone is thrown upward an initial speed of 20m/s. it goes up to a certain height, then comes down to the same level from where it was thrown. assume ag= -9.8m/s^s a. how high does the stone go before it starts to come down? how long does it take the stone to reach this point? b. what is the acceleration of the stone at the highest point it reached? what is its speed at the highest point? c. how long does it take the stone to reach the same level from where it was thrown??
10. ## How fast would a punch need to be for the shockwave to burst

This is an odd question, I know, but I watch plenty of crazy shows and they rub off on me. Say you are super fast and strong, and you see a nice puffy cloud 7500 feet in the air, a few miles away. Let's say you are capable of throwing a punch at hypersonic speeds, creating a wave of compressed air. Just about how fast would you need to punch to make a shockwave capable of busting the nice big cloud? You can make up your own calculations for how far the cloud probably is, as I assume you have a basic idea of what I want to know. Remember also, to take the size of the fist into account. I'd like the answer to be in mach number. I shall grant ten points to the genius who solves this for me
11. Thank you for replay. vt2 = v02 + 2ax here, x=h, a=g therefore, vt2= v02+2gh vt =v0 + gt therefore, t = vt + v0/ g substituting vt2 t2 = vt2- v02/ g2 t2 = v0 + 2gh - v02 t2 = 2h / g t = (2h/g)1/2 is it right ?? I'm Studying at 8th standard
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