leonne
Dec17-10, 09:07 PM
1. The problem statement, all variables and given/known data
2 particles are joined by mass less spring of length L. m2 initially resting on table and i am holding m1 vertically above m2 at height L. I project m1 vertically upwards with initial velocity Vo
find position of the two masses at any time and describe motion
2. Relevant equations
L=t-u
3. The attempt at a solution
I just need help finding the kinetic and potential of the system.
ok so in this system we have 2 potentials right? One is gravity and the other is the spring?
For the kinetic, we use the center of mass?
they get L= 1/2(M\stackrel{.}{Y}2-MgY+ 1/2(\mu\stackrel{.}{y}2-1/2(k(y-L)2)
for kinetic we use the center of mass formula right t=1/2MR2 +1/2(\mur2
Why exactly do they have Y than y is Y for mass 1 and y for mass 2? If so than the two potentials, one of them acts on one block and the other one on the other block?
o also how do we know when to use the center of mass formula? there was another problem with pendulum in a moving elevator and didn't use the center of mass formula
ok and to find position of the two masses, after solving the Lagrangian you are given equation of motion and i would think just take the derivative but thats not posible from the answer they get
Thanks
2 particles are joined by mass less spring of length L. m2 initially resting on table and i am holding m1 vertically above m2 at height L. I project m1 vertically upwards with initial velocity Vo
find position of the two masses at any time and describe motion
2. Relevant equations
L=t-u
3. The attempt at a solution
I just need help finding the kinetic and potential of the system.
ok so in this system we have 2 potentials right? One is gravity and the other is the spring?
For the kinetic, we use the center of mass?
they get L= 1/2(M\stackrel{.}{Y}2-MgY+ 1/2(\mu\stackrel{.}{y}2-1/2(k(y-L)2)
for kinetic we use the center of mass formula right t=1/2MR2 +1/2(\mur2
Why exactly do they have Y than y is Y for mass 1 and y for mass 2? If so than the two potentials, one of them acts on one block and the other one on the other block?
o also how do we know when to use the center of mass formula? there was another problem with pendulum in a moving elevator and didn't use the center of mass formula
ok and to find position of the two masses, after solving the Lagrangian you are given equation of motion and i would think just take the derivative but thats not posible from the answer they get
Thanks