Atwood machine - find kinetic energy

[NewJersey]

1) Massess of 1.00kg and 1.01kg are suspended in a frictionless Atwood machine
a) Find acceleration of the 1.010kg mass
b) Find the total kinetic energy of the masses 2.50s after being released

So for a I set up an equation where a= (1.01-1.00)
1.00+1.010 times 9/87m/s
and got .0491 for accelaration is this right.


b) I am confuse
Can anyone help

 

[rl.bhat]

Find the velocity of each mass using vf = vi + at. Then find KE.

 

[NewJersey]

so vf will equal
vf= (0.0491)*(3.8s)

Is part a right.

 

[andrevdh]

part a is correct

 

[andrevdh]

why do you take 3.8 seconds and not 2.50 seconds in the final speed calculation?

 

[NewJersey]

SO KE= 1/2 mv
so i would plugged in 1/2 times the total mass? * vf

IS this right, I will calculate the numbers later

 

[andrevdh]

Yes, but you need to square the speed.