Acceleration of block/pulley system

[genevieveb]

Homework Statement

What is the acceleration of the 2.0 block in the figure across the frictionless table?
Hint: Think carefully about the acceleration constraint.
I've attached the diagram.

Homework Equations

F=ma

The Attempt at a Solution

A=1.0kg block
B=2.0kg block
For block A: mAa1=2T
0=-Fg+n
For block B: mBa2=T-Fg
and no forces in x direction

So I assume the tension is equal because it is the same string. I also assume that the accelerations are different for the blocks though I'm not completely sure what to assume/why. All I really need is an explanation as to what I should know about the acceleration and why that is.

 

[PeterO]

Homework Statement

What is the acceleration of the 2.0 block in the figure across the frictionless table?
Hint: Think carefully about the acceleration constraint.
I've attached the diagram.

Homework Equations

F=ma

The Attempt at a Solution

A=1.0kg block
B=2.0kg block
For block A: mAa1=2T
0=-Fg+n
For block B: mBa2=T-Fg
and no forces in x direction

So I assume the tension is equal because it is the same string. I also assume that the accelerations are different for the blocks though I'm not completely sure what to assume/why. All I really need is an explanation as to what I should know about the acceleration and why that is.

That pulley system means that B will move half as much as A. half the distance, half the speed, half the acceleration.

 

[genevieveb]

Oh okay, that makes sense. Thanks a lot!