# Guillotine problem

1. Dec 3, 2009

### Sheldinoh

1. The problem statement

http://i868.photobucket.com/albums/ab249/sheldonsimon/ScannedImage.jpg" [Broken]
2. Relevant equations

I=.5MR^2

3. The attempt at a solution

mgh + .5mv^2 + Iw^2 = mgh + .5mv^2 + Iw^2

v=rw

I don't know if this is right or not.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited by a moderator: May 4, 2017
2. Dec 3, 2009

### rl.bhat

First of all using Newton's law and torque find the acceleration of the masses.

3. Dec 3, 2009

### Sheldinoh

can you explain that a little more. I'm sorry

4. Dec 3, 2009

### Sheldinoh

It would be 6m/s2 right?

5. Dec 3, 2009

6. Dec 3, 2009

### Sheldinoh

(M1+M2)a = M1(9.8) + M2(-9.8)

(20+5)a = 20(9.8) - 5(9.8)

a = 6

7. Dec 3, 2009

### rl.bhat

No. It is not correct.
Let T1 be the tension in the right segment of the string and T2 that of the left segment.
Then T1 - m1*g = m1a----(1)
R*(T2 - T1) = I*α-----(2)
m2*g - T2 = m2*a.----(3)
Substitute the values of I and α, and solve the equations to find a.

8. Dec 3, 2009

### Sheldinoh

Thank you so much. You are a life saver.