1
skygirl
·2009-01-18 04:50:16
we can conservve energy about point of contact since no slipping there..
so
U = 1/2 k x2 + 1/2 k x2 + 1/2 I ω2
= 1/2 k x2 + 1/2 k x2 + 1/2 (mR2 + 2/5 R2)ω2
diffrentiating both side,
0 = 2kx v + 7/5m v a
=> a = -(10k/7m) x
so, ω2 = (10k/7m)
bus [1]
24
eureka123
·2009-01-21 05:09:17
thanx sir..................sorry it came a bit toooo late.....
1
skygirl
·2009-01-18 18:46:56
oh shit.
it was a solid 'cylinder'... n i constantly read it solid 'sphere'...
dats y told diptosh n all incorrect.. [2] [2] [2]
I AM TOOOOO SORRY TO U ALL N MOST IMPORATNTLY MYSELF (for not able to materialise successfully my N-Y resolution [2] [2] .... bhaiya i will 'try' harder to avoid these... [2])
62
Lokesh Verma
·2009-01-18 07:54:28
sky, your mistake is that you have taken I corresponding to a sphere.. here it is a cyllinder...
Kep in mind that these misakes will kill all ur preparations... You have to not make these mistakes.... other mistakes are allowed...
62
Lokesh Verma
·2009-01-18 07:50:33
the total energy of the system is constant and then find its derivative..
E=1/2k(2x)2+1/2k(2x)2+1/2mv2+1/2 Icm(v/r)2
I=1/2Mr2
v=dx/dt
E=k(2x)2 + 3/4mv2
E=k(2x)2 + 3/4m (dx/dt)2
now take dE/dt=0
8kx(dx/dt)+3/2m(dx/dt) d2x/dt2 = 0
8kx+3/2md2x/dt2=0
d2x/dt2=-16k/3m x
hence 2pi √3m/16k
pi √3m/4k
1
skygirl
·2009-01-18 05:03:39
energy eqn ??
i am correct..
i have taken for point of contact..
u took it for com.
3
msp
·2009-01-18 05:02:43
dat x and v relation i think so leave it if i was wrong...
3
msp
·2009-01-18 04:58:35
oops sky u made a mistake
3
msp
·2009-01-17 10:44:16
Hint:
the total energy of the system is constant and then find its derivative..
E=1/2k(2x)2+1/2k(2x)2+1/2mv2c+1/Icm(vc/r)2
and x is the distance moved by com at a particular instant
1
skygirl
·2009-01-18 04:31:51
n no u are not correct :P
1
skygirl
·2009-01-18 04:26:41
ans is not that wat u gave diptosh..
its pi√3m/2k
62
Lokesh Verma
·2009-01-18 04:20:00
it is on the top and i think this is from Irodov.. a standard problem which is not very difficult...
I think the expression sankara gave is correct.. you just need to do a bit more to that
ie find the relation between v and x!
1
Diptosh
·2009-01-18 04:17:46
What's wrong with the springs at the top ?
Ans : pi √(3m/4k)
24
eureka123
·2009-01-17 10:47:55
Top..........maybe!!!!!!!
3
msp
·2009-01-17 10:47:53
Assume that the springs r at the topmost point...
1
Philip Calvert
·2009-01-17 10:44:36
hey those springs in the middle or on the top ?