Physics paper3: the discussion.

[Ahmedattia24]

Ok that wasn't an easy one. If you have any questions, please ask.

I'll start:

What was the answer for the water level in the matt black bulb and the other shiny white bulb?

What was the answer for the scientist/laboratory question concerning the speed of sound, the table was unreadable!

 

[wolf]

333.3m/s i guess... , and i think that the level of water will go up in the part of the tube where the shiny silver bulb was located and in matt black bulb part the level will go down...

 

[arabiannight975]

Exactly!!
the speed was 333.33 m/s and about that the level will go down asa the pressure will increase faster then the other one!

What was ur answer for the last question?

 

[XPFMember]

but i wrote that the level in the matt black bulb will go up since it absorbs heat and expands so volume increases and pressure decreases!And since that shiny one is a bad absorber there wouldnt be any change in that one!!

 

[Nouri Rock]

but i wrote that the level in the matt black bulb will go up since it absorbs heat and expands so volume increases and pressure decreases!And since that shiny one is a bad absorber there wouldnt be any change in that one!!

Same Answer I have answered !!!
And the speed is 333.3 m/s

 

[XPFMember]

yes speed is 333.33m/s if rounding shoul be atleast 3 s.f i guess!!

 

[wolf]

yes arabiannight, i've explained the question about bulbs exactly like you did=))

 

[SuperXDE]

There was a question I didn't understand , ¬¬ explain one after the 333.33m/s one , I don't really remember .. I think it was "Explain your ( something )"

 

[XPFMember]

it was write down any assumptions u made while calculating the speed

 

[karimehab]

What was the answer of the watts needed for the car question?

 

[XPFMember]

i dont remeber the answer but it was same as energy ,u just had to change units!

 

[XPFMember]

what did u all right for the effect of resultant force acting on a moving object perpendicularly to the direction of motion, it was so easy and i forgot ,i just wrote direction changes but when i asked teacher she said it will move in a circular motion!!

 

[Ivo]

what did u all right for the effect of resultant force acting on a moving object perpendicularly to the direction of motion, it was so easy and i forgot ,i just wrote direction changes but when i asked teacher she said it will move in a circular motion!!

Hmm, I said that there was no change. But I'm not sure. What was the exact question again?

 

[XPFMember]

It was like what will happen to the moving object when, (c) the resultant force is perpendicular to direction of motion?

 

[Ivo]

It was like what will happen to the moving object when, (c) the resultant force is perpendicular to direction of motion?

Apparantly someone who studys A-Level Mechanics said that perpendicular force doesn't change the motion.

 

[Ivo]

The question about what was assumed (when calculating speed of sound) and why was storm never passed directly overhead was also hard qs for me.

 

[XPFMember]

It was like what will happen to the moving object when, (c) the resultant force is perpendicular to direction of motion?

Apparantly someone who studys A-Level Mechanics said that perpendicular force doesn't change the motion.

no, remember that direction of the force acting on an object moving in circular motion was perpendicular to the direction of motion -100% sure cuz this direction has been asked in 2007 or 2008

 

[Ivo]

It was like what will happen to the moving object when, (c) the resultant force is perpendicular to direction of motion?

Apparantly someone who studys A-Level Mechanics said that perpendicular force doesn't change the motion.

no, remember that direction of the force acting on an object moving in circular motion was perpendicular to the direction of motion -100% sure cuz this direction has been asked in 2007 or 2008

However, perpendicular is ambigious. It good mean like you said, resultant force to the side of the car, but also it can be to the top of the car (or bottom), so a bit ambigious.

 

[XPFMember]

The question about what was assumed (when calculating speed of sound) and why was storm never passed directly overhead was also hard qs for me.

assumption was asked in one the pastpapers but i forgot it i think it was speed of light is negligible,i wrote a big paragraph for that one mark as i wasnt sure exactly whats the ans.!
and ffor that storm never passed i guess i wrote the time decreases till (dont remember the value ) and again starts to increase so always takes some time to reach!

 

[XPFMember]

However, perpendicular is ambigious. It good mean like you said, resultant force to the side of the car, but also it can be to the top of the car (or bottom), so a bit ambigious.