Investigating a Bending Bridge.

Investigating a Bending Bridge

PLANNING SECTION

Introduction

In this investigation I am going to investigate two factors. Firstly how the sag varies with an increase in weight. Secondly how the sag varies with a varying pivot (distance from the end of piece of wood).

The sag is the extension of the bridge (piece of wood). This can be seen in diagrams below.

No Mass Mass

Weight

This distance is what is referred to as the sag

Apparatus List

For both experiments I used the same equipment, which included:

Retort Stand x3
Ruler (100cm) x1
Length of wood (90cm) x1
String x1
Optical Pin x1
Cello tape x1
Weights (50g) x4
Weight with hook (50g) x1

Preliminary Work

I have previously studied Hooke’s Law, so referred to GCSE Physics Third Edition by Tom Duncan. It states here that the extension is directly proportional to the force applied. I think that this is going to be relevant in my investigation although Hooke’s Law is in reference to a spring. I also investigated constants and variables for my two experiments, which I must keep the same in order to make it a fair experiment.

Constants

I must keep things constant to ensure that I have planned and then carried out a fair experiment.

Experiment A

The position of the weight must be in the same position. If it weren’t it would mean that the moments on each side would be different. This could affect my results adversely.
The distance from the end of the piece of wood. This is because I am only investigating this experiment with varying weight. (100mm)
The length of the bridge (900mm)

Experiment B