Author Topic: Physics Help HERE ONLY !!  (Read 80832 times)

Offline hmh

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Re: Physics Help HERE ONLY !!
« Reply #825 on: June 09, 2009, 09:58:38 pm »
hi ... !! ok i have two questions it's from past papers June and November 03 :

1- the mass of a full bottle of cooking oil is 1.3 kg when exactly half the oil is used  the mass of the bottle and the remaining oil is 0.9 kg what is the mass of the bottle ? now i know it's ''B'' but how ??

2- the half life of a radioactive substance is 5 hours a sample is tested and found to contain 0.48 g of the substance how much of the substance was present in the sample 20 hours before the sample was tested ?? i also know its ''D'' but again how ??

thanks and +rep for anyone who answers =]

For no.1 : first find the mass of the half of oil( 1.3-0.9=0.4), then u know that other half is 0.4 too. So, subtract the whole mass of oil (0.4*2) from the mass of bottle and oil (1.3) to get 0.5kg
For no. 2: Half life(time for value to half) is 5 hours, and there are 4  5s in 20(meaning you'll have to multiply 0.48 by 2  4 times to get the value 20 hours before decay
so, finally, you'll get 7.68g

I hope this helped

OK so 1 is B i dnt knw the value because i didnt look at exam but shud be 0.25kg becuz.. 1.3/2 = 0.65 half left... but we got 0.9 kg as mass so 0.9-0.65 = 0.25 kg mass of bottle.

2 .. again didnt look at the paper.. but guessesing tht answer shd be 1.92g... as 4 half lives reversed as of 5 hrs 1 time.. so 0.48*4 = 1.92.

yea lol.. i corrected myself :P thanks anyway
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Offline MR.BooMBastiC

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Re: Physics Help HERE ONLY !!
« Reply #826 on: June 09, 2009, 10:02:48 pm »
anything else lana

i will be more than happy to help u...

Offline lana

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Re: Physics Help HERE ONLY !!
« Reply #827 on: June 09, 2009, 10:05:29 pm »
thank uuu sooo much =]
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Offline Petrol

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Re: Physics Help HERE ONLY !!
« Reply #828 on: June 09, 2009, 10:11:40 pm »
heyy november 2003 question 3 it doesnt make sense are u sure the mark scheme is correct i think it should be D but it says A :s

Offline MR.BooMBastiC

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Re: Physics Help HERE ONLY !!
« Reply #829 on: June 09, 2009, 10:12:12 pm »
no problem

it was nice talking to u!! ;) :)

Offline lana

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Re: Physics Help HERE ONLY !!
« Reply #830 on: June 09, 2009, 10:15:52 pm »
ya it's A because the car starts to accelerates so it's slowest at the start then the speed increases until it reaches pole 4 and stays at the same speed !! hope u got it

and MR.BooMBastiC ! it was great talking to u 2 =]
« Last Edit: June 09, 2009, 10:17:55 pm by lana »
''To be yourself in a world that is constantly trying to make you something else is the greatest accomplishment.''

Offline hmh

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Re: Physics Help HERE ONLY !!
« Reply #831 on: June 09, 2009, 10:16:22 pm »
heyy november 2003 question 3 it doesnt make sense are u sure the mark scheme is correct i think it should be D but it says A :s

It should be A.. as it asks for the most/ greatest time to pass throught poles.. so tht is 1 and 2 wen the car is slowly accelerating to high speed.
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Offline astarmathsandphysics

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Re: Physics Help HERE ONLY !!
« Reply #832 on: June 09, 2009, 10:16:48 pm »
heyy november 2003 question 3 it doesnt make sense are u sure the mark scheme is correct i think it should be D but it says A :s

it is a

it takes longest when it is travelling slowest ie between the first 2 poles

Offline MR.BooMBastiC

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Re: Physics Help HERE ONLY !!
« Reply #833 on: June 09, 2009, 10:26:04 pm »
U R  right!!  astarmathsandphysics


nid404

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Re: Physics Help HERE ONLY !!
« Reply #834 on: June 10, 2009, 07:33:27 am »
U are so unkind u swine...

People need to get into university, and i am helping people with it!!!

if ur so confident of ur answers, keep them to urslf, or contribute like me!

By the way crudity is not tolerated..

u have been reported..the moderator will decide ur fate

Offline esso

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Re: Physics Help HERE ONLY !!
« Reply #835 on: June 10, 2009, 07:38:39 am »



thats wat he deserves......kicked out of this forum....

i saw this answers bt they r wrong...most of dm,,,,,

u know i just came from the exam....its easy .... does not require cheating at all....

nd with this cheated answers u ll get less marks then u coud have got....

nid404

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Re: Physics Help HERE ONLY !!
« Reply #836 on: June 10, 2009, 07:40:43 am »



thats wat he deserves......kicked out of this forum....

i saw this answers bt they r wrong...most of dm,,,,,

u know i just came from the exam....its easy .... does not require cheating at all....

nd with this cheated answers u ll get less marks then u coud have got....


Thanks for the support :)

Offline Friends

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Re: Physics Help HERE ONLY !!
« Reply #837 on: June 10, 2009, 07:43:22 am »
His most the answers are wrong. Definitely last 2 are wrong.



And plzzz moderater dont ban me for this:

ANSWERS GO F**K URSELF.
« Last Edit: June 10, 2009, 07:46:38 am by Friends »

Offline esso

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Re: Physics Help HERE ONLY !!
« Reply #838 on: June 10, 2009, 07:50:15 am »
+rep for u all for keeping the forum clean.....

nid404

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Re: Physics Help HERE ONLY !!
« Reply #839 on: June 10, 2009, 07:51:34 am »
+rep for u all for keeping the forum clean.....

for u too...but the forum is not clean cuz the site is still in many threads and circulating. I hope the moderator reviews this and takes action