# Force problems

1. Oct 2, 2007

### lim

1. The problem statement, all variables and given/known data

One 3.90 kg paint bucket is hanging by a massless cord from another 3.90 kg paint bucket, also hanging by a massless cord, as shown in figure below. If the buckets are at rest, what is the tension in the lower cord? What is the tension in the upper cord?

2. Relevant equations
Tlower = ma + W
F=ma

3. The attempt at a solution

T = (3.9)(0) + 9.8

T= 9.8 N

?
I wasn't getting the lower tension right, so I figured I should find out how to do that first, hence no work for the upper tension.
Any help appreciated

Last edited: Oct 2, 2007
2. Oct 2, 2007

### Kurdt

Staff Emeritus
The weight of an object is given by the product of its mass and the acceleration due to gravity.

3. Oct 2, 2007

### lim

Ohh. So, the tension of the upper cord is Tu = ma + W + Tl, so Tu = 0 + 38.2 + 38.2N, Tu = 76.44 N.
Thanks!

4. Oct 2, 2007

### Kurdt

Staff Emeritus
Just remember that weight is the force on an object due to gravity. It can sometimes get confusing because it has its own name but its just given by F=ma where a is the acceleration due to gravity.