Question 144
This project is about using moments to find the weights of objects. You will make a balance and then use it to find some unknown weights.
Background: The earliest balances for weighing needed equal weights on both sides of the balance. The unknown weight was placed on one side, and known weights were added on the other side until the system was balanced. A system such as this is balanced because there are two moments acting. One moment tries to pull one side down. The other moment tries to pull the other side down. When the moments are equal and opposite, the system is balanced. This happens when the weights are equal because the distances from the pivot are also equal.
Your task: Make a balance that can be used to weigh a range of different weights without changing the known weight. Your balance will work in a different way to the one in the picture, so yours will not look like this. Work in groups. You can use equipment such as: a metre rule; a triangular prism; a known weight; any other equipment that your teacher makes available.
Remember: do not confuse weight with mass; weight is a force; the moment caused by a force depends on the distance from the pivot. When your balance is made and working, you can demonstrate to the class how it works.
Background: The earliest balances for weighing needed equal weights on both sides of the balance. The unknown weight was placed on one side, and known weights were added on the other side until the system was balanced. A system such as this is balanced because there are two moments acting. One moment tries to pull one side down. The other moment tries to pull the other side down. When the moments are equal and opposite, the system is balanced. This happens when the weights are equal because the distances from the pivot are also equal.
Your task: Make a balance that can be used to weigh a range of different weights without changing the known weight. Your balance will work in a different way to the one in the picture, so yours will not look like this. Work in groups. You can use equipment such as: a metre rule; a triangular prism; a known weight; any other equipment that your teacher makes available.
Remember: do not confuse weight with mass; weight is a force; the moment caused by a force depends on the distance from the pivot. When your balance is made and working, you can demonstrate to the class how it works.
