The magic of torque

Meter stick challenge

Earlier this week Emma and I were tasked with finding the weight of a meter stick by using a 100 gram weight. To tackle the task we used our knowledge of torques and lever arms to help us.

Steps to complete the task

1   1)      Attach the weight at the end so the weight is evenly distributed over the edge.

2   2)      Balance the stick to find that it will balance 25 cm from the end with the weight.

3   3)      Create an equation so that both torques are equal.

4   4)      Solve for weight.

Equation for torque

Force * lever arm = Torque

.98*25 cm = Torque

Since both torques had to be the same for the stick to balance solving for weight of the stick is as easy as making sure the forces were equal, revealing the weight of the stick at 98.1 grams.

Looking back

I wish that I had helped Emma understand the concept better, since I feel as though I took the driver’s seat. I also wish I had been a smidge more precise in my calculations as we still had a 1% error.