Author Topic: Physics Help HERE ONLY !! (Read 80921 times)

Shogun · « **Reply #300 on:** June 02, 2009, 06:37:01 pm »

lol astar, u ever made an atom bomb?.... ;Dlol

ny · « **Reply #301 on:** June 02, 2009, 06:41:51 pm »

Quote from: astarmathsandphysics on June 02, 2009, 06:36:14 pm

nuclear fusion is what happens to make stars shine eg 4p¹⁺>He²⁺+2e⁺ atoms fuse to make bigger atoms

fission is what happens in atom bombs eg ²³⁶U>¹⁴¹Ba+⁹²Kr+3¹n atoms split to make smaller atoms

okay.thanks.

nid404 · « **Reply #302 on:** June 02, 2009, 06:46:35 pm »

some1 wanted help wid lenz's law..im really bad at explaining physics
superb ppt attached check it out

Shogun · « **Reply #303 on:** June 02, 2009, 06:49:13 pm »

nid ure making these ppt?

nid404 · « **Reply #304 on:** June 02, 2009, 06:50:48 pm »

not physics......these i get from the net

but yes for eco and bio i do

Shogun · « **Reply #305 on:** June 02, 2009, 07:00:06 pm »

lol, thst g8 Thanks

islu_jf · « **Reply #306 on:** June 02, 2009, 07:47:59 pm »

can anybdy plz tell me .. what is the diff By the way a motor and a generator??

12345abc · « **Reply #307 on:** June 02, 2009, 09:36:48 pm »

a glass jug is designed so that it does not break when boiling water is poured...what type should be used?
thick or thin AND should expand little/more when heated???
plz explain as well

-))((-S.U.B-))((- · « **Reply #308 on:** June 02, 2009, 10:12:08 pm »

Guyz what does the following (in red) means:

-state and use the symbols for logic gates
(the American ANSI#Y 32.14 symbols will be used)

Its a line from the syllabus

idol2009 · « **Reply #309 on:** June 03, 2009, 05:11:31 am »

Hey, I was doing the Oct/Nov 08 Paper 3, and on question 5c), it asks you to calculate the specific latent hear of fusion of ice from the results they have given you...
I usually find this pretty straightforward, but on this problem I was kind of stuck, because my answer didn't match the mark scheme...
The question goes as follows:
"Using a 40W heater, 16.3 g of ice is melted in 2.0 minutes. The heater is then switched off. In a further 2.0 minutes, 2.1 g of ice is melted.
Calculate the specific latent heat of fusion of ice from these results."

So I basically did the following calculation:
Total Energy supplied = 40 x 120 = 4800 J
Total Mass melted by heater = 16.3 g
Specific latent heat = 4800/16.3 = 294.5 J/g

I don't understand what I've done wrong, and what the switching the heater off and the further 2 mins has to do with it?
Any help would be appreciated thanks!

Friends · « **Reply #310 on:** June 03, 2009, 06:08:40 am »

Hey someone plz put up all the units.
Like force-NEWTON

Q80BOY · « **Reply #311 on:** June 03, 2009, 07:32:14 am »

Units:

quantity - unit - symbol

Mass - Kilogram - Kg

Length - Metre - m

Time - Second - s

Area - Square metre - m^2

Volume - Cubic metre - m^3

Force - Newton - N

Weight - Newton - N

Pressure - Pascal - Pa

Energy - Joule - J

Work - Joule - J

Power - Watt - W

Frequency - Hertz - Hz

PD, EMF, Voltage - Volt - V

Current - Ampere - A

Resistance - Ohm - _()_ <-- thats the ohm sign

Charge - Coulomb - C

Temperature - Kelvin - K

Temperature - degrees Celcius - *C

hope this helps

Friends · « **Reply #312 on:** June 03, 2009, 07:36:38 am »

Thanx man
+ rep for u

Q80BOY · « **Reply #313 on:** June 03, 2009, 07:40:54 am »

Quote from: Friends on June 03, 2009, 07:36:38 am

Thanx man
+ rep for u

Thanks

IGSTUDENT · « **Reply #314 on:** June 03, 2009, 07:42:35 am »

Quote from: nid404 on June 02, 2009, 06:46:35 pm

some1 wanted help wid lenz's law..im really bad at explaining physics
superb ppt attached check it out

Do we need to cover this lenz law?

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