Physics p22

[turboboy]

i did exactly what hassam bro said ( rain drop graph ) , Young modulous can be explained in lots of way as long as it makes sense. About the roller coaster question : Kinetic energy 27KJ , potential was proved 24KJ , therefore Energy lost due to resistive force 3KJ. the distance travelled at 30degrees was found by sin rule , then energy= force times distancs , energy here is 3KJ distance we knw so the resistive force was found.

 

[turboboy]

OH and the circuit ques , the current was 2.5A , then 30watt , enery lost i did a vert silly mistake by not addind the power lost in battery A with the external resistance. But still the power lost was less than produced so the last question was proved that surplus energy was stored in battery B

 

[boy2011]

for the last part of ths energy questn in whch we hav to found d we need to write lyk ths w=f.d.cos30 because angle was wd horizöntal?

 

[hassam]

yar did all of u for calculating acceleration....calculated mass and then substituted into a=f/m....tell me...and this F was calculated in previous part ....wat was this F....drag force.........?? or....tell me m confused abt one thing

 

[hassam]

guys...wat was ur a..was it 4.9.....?????

 

[fahadii92]

o

 

[hassam]

yar wat was ur accelration....did u used drag force to find it or resulatnt force???/

 

[hassam]

i m really confuse at the moment..bt i thinkk they ll never give such a difficult concept in a 2 mark question......will they?

 

[aashish]

guys how didi u calculate the power. which formula u used in calculating electricity. pls tell me

 

[jason3991]

what was resultant velocity in first question??? was it 22m/s?

 

[hassam]

ya ............if anybody cud post details of that drag force question....i will be very grateful......

 

[boy2011]

resultant velocity was 26. Sumthng..:s

 

[yaogeorge]

u mean the acceleration ? i think need use mg-friction=ma to find a.. and the graph is above the original graph..reach terminal velocity in shorter time..

 

[workinghard]

k hassam
sory lite went out
ma ans is same as urs 4 acc
lets hope itx rite...

 

[xenvox]

Acceleration was 4.9

 

[sniper7137]

Yeah mine was also 4.9 ms^-2 as well. In the Young Modulus question i told to draw up a graph of force on y-axis and extension on x-axis. Find its gradient and multiply it by (original length / cross section area). The apparatus was the wire itself hung from a ceiling with a pointer and weight hanger attached to its bottom. The pointer points to a measuring scale also attached to the ceiling and in line with the wire and a micrometer for the radius? What do u think? Is that OK? And what was your wavelength in the last question? Mine was 639 nm.

 

[hassam]

there is one problem more than HALF OF guyx did....we dint use resultant force to find a ...i guess...did [email protected] u remember ur anser

 

[hassam]

wat do u think sniper7137....? cos drag force will not give a...or previous part already said to determine the resultant force....?

 

[sniper7137]

We did. We had to subtract the drag force from the weight of the drop to get the resultant force. I made that very mistake earlier in the paper. I found acceleration from the drag force directly. Then i remembered that we had to subtract it from the weight. The answers either way are pretty close.

 

[hassam]

hmm...last question....in previous part ....did he asked to calculate drag force or...resultant force...just tell me this did the question ever ask us to find it ....if not hen m loosin 2 marks i guess