discussssss the ATP PHYSICSSSSSSS

[Angraiz]

May/June 07 gives 2,4 and 5 as correct answers.

A larger number of readings helps a better graph to be plotted. Did you see the graph? It was difficult to join the last two readings because there was such a large gap. Taking more readings will make shape of graph more accurate.

95cm=5cm which was 1.61s I think. 50cm would'nt work as the rule is at equilibrium and it won't oscillate.

 

[JAMES SMITH]

Angraiz r u sure that at 50cm it wont oscillate i also wrote the same and added it will be in rotational equilibrium and most of my frnds said a couple will be produced

 

[Angraiz]

Yes it wont oscillate and it wont swing properly, it will continue to rotate.

 

[JAMES SMITH]

what do u think writing only that it will be in equilibrium is it sufficient

 

[UxaiR]

the question does not required to tell whether it was equilibrium or not. !

all you people have to tell was that 50 cm is center of gravity of the mass ,, hence it would not oscillate and would rotate 360`.!!!!! =)

 

[beststriker]

What was the motor efficiency according to the formula. it was around 14 or should be written as 0.14.

 

[JAMES SMITH]

MORE EXACT WAS IT WAS IN ROTATIONAL EQUILIBRIUM
14.48 OR 14.14 SOMETHNG LIKE THAT
what did u write to that why a student draws a line round the block

 

[Jezla]

Thank God, that's a relief!!

Now that takes my relief. Dammit! Now my answer is wrong!

One never knows accurately if my answer was ryt or yours.

 

[UxaiR]

MORE EXACT WAS IT WAS IN ROTATIONAL EQUILIBRIUM
14.48 OR 14.14 SOMETHNG LIKE THAT
what did u write to that why a student draws a line round the block

Q.why a student draws a line round the block
A.so that the student could place the prism back to it's original place once removed from it's mean position .!

 

[beststriker]

where was the prism..............

 

[JAMES SMITH]

the block
he must be sure that where he had placed the block if the block is misplaced
i think this will also do

 

[UxaiR]

yes the block .!
sorry i forgot it was not a prism .! lol

 

[geisha69]

2 AND 4 WERE CORRCET 100% CONFIRMED FACT

2 was using 2 students right?

I think the last 2 boxes were right, namely taking a wide range of readings, and transferring the oil quickly to the beaker.

Why was number 2 wrong? Because:
2 people should/are used for experiments when 2 quantities have to be measured, or 2 tasks have to be done in a SHORT amount of time, i.e less than a few seconds. 1 person cannot do both tasks within the time, so 2 people are used.

In this experiment, the tasks were to heat the oil, take its temperature, transfer it to the beaker, and then take the temperature of the oil every 30 seconds (I think). This is not a short amount of time, and all these tasks can be EASILY performed by 1 person, without it causing any inaccuracies in the experiment.

Number 4; taking wide range of readings was right because taking many readings results in a more accurate graph being plotted, thus a clearer picture of the rate of cooling can be obtained, which is what you need.

Number 5: Transferring the oil quickly to the beaker was important because not doing this will make the experiment inaccurate. Suppose the oil is heated and the temperature is 69. If transferring takes a while, the temperature will decrease, and the actual temperature will be lesser than 69, say 68, and will result in an inaccurate graph being plotted. Transferring it quickly will ensure that the temperature of the oil measured is indeed the actual temperature of the oil when it is cooled in the beaker.

A.

i also ticked 4 and 5 .! but i am unsure about the one about 2 people .! :roll:

 

[geisha69]

how was the ray 3 drawn??? i'm really confused...'cause i drew normals and measured the angles and took the refractive index and then drew it accordingly........though, it was bending in the correct direction, it was not intersecting the ray 1 and ray 2 at the same point....is it wrong....????
for those wondering why i did it, it was because i had much time left =P...=D...)=...D=........but will it make my answer wrong?

 

[hassam]

i did da same and its surely true b coz i have seen a similar questionm elsewhere we had to do the same accordind to the ms of that ques

 

[jafar]

i thinl it wud be rong b/c the rays were bending 2wards each other nd were interseting after leaving the block. :S

 

[JAMES SMITH]

for ray 1 join with emergent ray
for 3 left side intersecting ray 1 about 0.75cm

 

[habib123]

yar damn i wrote 100c is that alrite? or 110 was th only rt answer?

 

[A.RK kamal]

Well!!! I asked my teacher about the Q1 last part in whick 2 boxex were to be ticked.(He is teaching at lycium and other 2 schools aswell). He said that quickly pouring the oil will minimize the heat loses,therefore necessary for accuracy and using long range of readings will also help in improving the experiment. in short last two boxes are perfectly correct)

 

[hussam]

The angle of i will have 2 ranges, one of them is 32 to 36(or might be till 38) the other im not sure about but there would be because I have seen a similar Q n there were two answers for the angle.
Gently heated because the oil would start evaporating if exposed to high heating temperature.
When heated in a beaker it wont catch fire and the thing is that it does evaporate but slowly.