How was physics paper 4

[HunzaZ]

i did do it in metres for the calculation for energy, but i have a strong feeling it ws written in cm in the q for equation cuz before putting the values i ws seriously considering whether they wanted it in m or cm,,,,oh well maybe i did write 0.021

Question clearly said "in cm"

 

[Akri123]

Erm weren't we supposed to replace the 'w' with the angular velocity thingy? Given that the question did ask us to write with respect to t or something? lol Or maybe I'm wrong. Whatever.

 

[ganapathynar]

Erm weren't we supposed to replace the 'w' with the angular velocity thingy? Given that the question did ask us to write with respect to t or something? lol Or maybe I'm wrong. Whatever.

i think you were supposed to

 

[ganapathynar]

Wasn't the temp below 297? It was, gas was expanding, it cools on expanding.

i interpreted the question a whole different way!

 

[Akri123]

Yeah, that's what I thought! haha.

 

[HunzaZ]

i interpreted the question a whole different way!

That's just a general thing, I obviously didn't write that. Used the formula U= q + w and q was zero while w was negative because work was being done by the gas to push back the piston and not on the gas. Hence U was negative, and decrease in internal energy suggests a lower temperature.

 

[ganapathynar]

That's just a general thing, I obviously didn't write that. Used the formula U= q + w and q was zero while w was negative because work was being done by the gas to push back the piston and not on the gas. Hence U was negative, and decrease in internal energy suggests a lower temperature.

I thought the statement about the gas expanding against the pressure and doing 150 J of energy, was a general statement and i took the first line of the problem that is: The volume of gas remains constant and said that 150 J of energy is done on the gas, causing to keep it at constant volume, so internal energy increases and therefore temperature rises.

 

[HunzaZ]

I thought the statement about the gas expanding against the pressure and doing 150 J of energy, was a general statement and i took the first line of the problem that is: The volume of gas remains constant and said that 150 J of energy is done on the gas, causing to keep it at constant volume, so internal energy increases and therefore temperature rises.

Dont exactly remember if it said volume was to remain constant

 

[ganapathynar]

Dont exactly remember if it said volume was to remain constant

that is the thing the first sentence said so.

 

[FRENZYAMU]

Wasn't the temp below 297? It was, gas was expanding, it cools on expanding.

dont say that u agree Hunza ! XD, i wrote temp rises, how much marks lost ? 3 ?

 

[FRENZYAMU]

Question clearly said "in cm"

yay i KNEW IT!!!!!! up top girl !

 

[Your-Blood]

Alright then did we need to calculate everything in cm too?

 

[ganapathynar]

Alright then did we need to calculate everything in cm too?

only amplitude

 

[ganapathynar]

yay i KNEW IT!!!!!! up top girl !

But the velocity was in m/s

 

[FRENZYAMU]

But the velocity was in m/s

was it ? i dont remember if they had a diff statement for velocity too, but i just know s was to be in cm

 

[HunzaZ]

that is the thing the first sentence said so.

I believe I read it very carefully and didn't find a thing such but anyways if that's so then you're right. More marks lost :/

 

[HunzaZ]

dont say that u agree Hunza ! XD, i wrote temp rises, how much marks lost ? 3 ?

The other guy says I misread the question because if the volume was to stay constant then probably its the other way round :s Cuz I read as volume to be increasing i.e. work being done 'by' the gas, that is negative work done so negative internal energy and temperature decrease but if the volume was staying constant and the piston wasn't moving, I've lost marks :s

 

[FRENZYAMU]

The other guy says I misread the question because if the volume was to stay constant then probably its the other way round :s Cuz I read as volume to be increasing i.e. work being done 'by' the gas, that is negative work done so negative internal energy and temperature decrease but if the volume was staying constant and the piston wasn't moving, I've lost marks :s

u knw i still believe it shud be half of 2.1,,,,,idk it has taken roots in my mind

 

[FRENZYAMU]

I believe I read it very carefully and didn't find a thing such but anyways if that's so then you're right. More marks lost :/

nd what about velocity being in m/s, i didn't convert it into m for velocity either !

 

[TaffsAsLevel]

I got mass of sun 2x10^30 I checked on google and it was correct hahaha