- #1

jesuslovesu

- 198

- 0

**[SOLVED] Block on a table**

## Homework Statement

http://img91.imageshack.us/img91/4285/fudgepq5.th.png

I am having some trouble finding the acceleration of the blocks, can anyone help me?

The weight of B is 6 lbs.

The weight of A is 5 lbs.

The friction coef is .3

## Homework Equations

## The Attempt at a Solution

1) The positive y-axis goes from left to right

sum of forces in y = (6/32)*ab = 2T - 1.8

2) positive y-axis goes from top to bottom

sum of forces in y = (5/32)*aa = 5-T

I know that aa = -2ab

The way my book derives the relationship between aa and ab is from 'dependent motion' they say that length = sa + 2sb and taking the time derivative twice is 0 = aa + 2ab, the problem is with the way I have my equations setup, when i use aa = -2ab i get the wrong answer, does anyone know how I can fix it so I am using aa = -2ab and getting the correct answer?

I don't see anything wrong with my equations, but i am getting the wrong accelerations. Can anyone help?

Last edited by a moderator: