Physics Unit 4 JUNE 11/6/12

[*Sandra*]

yes for maximum enegry transfer :to occur

ok i wil tel u how i wrote it : they absorb energy from the oscillation of the bridge and dissipate it into the surrounding. this reduces the amplitude of oscillations exponentially avoiding resonance whch cld cause the bridge 2 collapse and it shld be heavily damped 2 prevent large amplitude build up ? it it correct i fel there's smethng wrng

 

[*Sandra*]

i

I solved question 5 and 6 as well, what did u want to know in dat?

wnted q(5) last part and q(6)

 

[étudiante]

ok i wil tel u how i wrote it : they absorb energy from the oscillation of the bridge and dissipate it into the surrounding. this reduces the amplitude of oscillations exponentially avoiding resonance whch cld cause the bridge 2 collapse and it shld be heavily damped 2 prevent large amplitude build up ? it it correct i fel there's smethng wrng

well it doesnt "avoid" resonance, it only transfers the energy to the spring which are stiff so they dissipate the energy and are damped so can't vibrate.Since there is less energy, the bridge wont vibrate either.
Resonance still occurs, but its effect is reduced

 

[étudiante]

i
wnted q(5) last part and q(6)

Q5) well the car will move up and down with the bridge right? but when comming down, the ony force on it is gravity and the acceleration due to that is 9.8 which is less that that of the bridge. This means the bridge will be down and the car will still not have travelled that distance so it will loose touch

Q6) which part? (btw, i dont think they specified what is f(nought) :S)

 

[*Sandra*]

well it doesnt "avoid" resonance, it only transfers the energy to the spring which are stiff so they dissipate the energy and are damped so can't vibrate.Since there is less energy, the bridge wont vibrate either.
Resonance still occurs, but its effect is reduced

so when the bridge oscillate due to people walking it wil then reach its natural frequency and since the dampers are tuned to the bridge's natural frequency so the bridge transfers energy 2 them? and why they say havily damped they mean abt the bridge or the dampers?

 

[*Sandra*]

Q5) well the car will move up and down with the bridge right? but when comming down, the ony force on it is gravity and the acceleration due to that is 9.8 which is less that that of the bridge. This means the bridge will be down and the car will still not have travelled that distance so it will loose touch

Q6) which part? (btw, i dont think they specified what is f(nought) :S)

1st part the exp part?

 

[étudiante]

so when the bridge oscillate due to people walking it wil then reach its natural frequency and since the dampers are tuned to the bridge's natural frequency so the bridge transfers energy 2 them? and why they say havily damped they mean abt the bridge or the dampers?

it can be ppl or wind or nething acctually and its IF it reaches its natural frquency (a precaution really )

They're talking about the bridge and the dampers (in the dampers its due to their stiffness)

 

[étudiante]

1st part the exp part?

u want me to tell u the experiment? U need to give the spring a pull-and-release, then record the time for 20 oscillations and divide the time by 20. Repeat and average. Ensure that the oscillations are in a straight line only
(This is part of Unit 6 btw )

 

[*Sandra*]

u want me to tell u the experiment? U need to give the spring a pull-and-release, then record the time for 20 oscillations and divide the time by 20. Repeat and average. Ensure that the oscillations are in a straight line only
(This is part of Unit 6 btw )

ohh thnx alot and sry 4 disturbing u alot

 

[étudiante]

ohh thnx alot and sry 4 disturbing u alot

ur so welcome n PULEEZ! Ur not disturbing me a BIT! Infact ur forcing me to study physics so i should thank you for that

What are you doing now, as in revising what?

 

[*Sandra*]

ur so welcome n PULEEZ! Ur not disturbing me a BIT! Infact ur forcing me to study physics so i should thank you for that

What are you doing now, as in revising what?

im solving ques's for nuclear physics wat abt u?

 

[étudiante]

im solving ques's for nuclear physics wat abt u?

Nuclear physics
Im still doing the oscillations questions, but m bored now
I think i'll switch to Astrophysics for a while >.<"

 

[*Sandra*]

Nuclear physics
Im still doing the oscillations questions, but m bored now
I think i'll switch to Astrophysics for a while >.<"

happy time wth astrophysics

 

[étudiante]

happy time wth astrophysics

thanks!
Though i think it'll be more like torture
U'll enjoy wid Nuclear Physics (Its one of the few chapters that make ne much sense to me )

M logging off now btw, I'll come again in the evening/night Inshallah... just post if u need nething
Bye ^_^

 

[*Sandra*]

thanks!
Though i think it'll be more like torture
U'll enjoy wid Nuclear Physics (Its one of the few chapters that make ne much sense to me )

M logging off now btw, I'll come again in the evening/night Inshallah... just post if u need nething
Bye ^_^

bye tc

 

[*Sandra*]

thanks!
Though i think it'll be more like torture
U'll enjoy wid Nuclear Physics (Its one of the few chapters that make ne much sense to me )

M logging off now btw, I'll come again in the evening/night Inshallah... just post if u need nething
Bye ^_^

heyy.. i wanna ask u did u solve sample's assesment material?

 

[étudiante]

heyy.. i wanna ask u did u solve sample's assesment material?

I'll be doing them tonight
I'm here now btw

 

[*Sandra*]

I'll be doing them tonight
I'm here now btw

i hate astrophysics and yet i didn study anythng it u can say i kno nthn in it hope i'll be able 2 finish my studies as soon as possible

 

[étudiante]

i hate astrophysics and yet i didn study anythng it u can say i kno nthn in it hope i'll be able 2 finish my studies as soon as possible

SAME HERE I said i'll do it that time but i only got as far as the gravitation parts
Inshallah u will dw

 

[*Sandra*]

no

SAME HERE I said i'll do it that time but i only got as far as the gravitation parts
Inshallah u will dw

seriously i didn study it ever b4 like 2day im studying frm the begining and past papers r wonderful 4 the ques's