# Investigating a Cantilever.

Investigating a Cantilever

Research

A cantilever is a beam fixed at one end only. They are often used in every day life in structures such as cranes, diving boards and football stadiums.

Factors that effect the deflection of a cantilever are mass, length and load.

3 forces affect a cantilever’s deflection; these are gravitational forces acting upon the mass and load of a cantilever a compressional force acting on the underside of the cantilever and a tensional force on the upper side of the cantilever. If the cantilever deflects too much it will break.  This is either because it is too long or too much weight is acting upon it.

Tensional Force                                Compressional + Tensional Force

Compressional Force                                Weight (Mass x Gravitational Force)

I’m going to investigate how changing the load will effect the deflection of the cantilever.

Preliminary Test

The Preliminary test was taken to find the optimum length of the cantilever for our investigation, a compromise between a very large and very small deflection, one that was measurable and easy to take readings off of. Also a perfect length so that the cantilever is safe and isn’t likely to break.

These are results of our preliminary test

From these results we decided that 500mm was the optimum length of the cantilever.

Method

Our equipment for the investigation will be:

• A wooden metre ruler-the cantilever
• A G Cramp to secure the cantilever to the lab bench
• A second meter ruler to measure the deflection of the cantilever
• 5x100g weights
• A mirror and pin
• We shall use mass’ of 100-500g at 100g intervals

G-Cramp        Cantilever         Pin         Mirror                Ruler

We are going to fix the cantilever to the lab bench at a length of 500mm ...

#### Here's what a teacher thought of this essay

This is a well written report on an investigation. 1. The background section is very concise and well researched. 2. The preliminary results is relevant to set up the investigation. 3. The method and results are well structured. 4. The analysis section is well written but brief. 5. The evaluation contains good suggestions but the language used is not as concise as previously. **** (4 stars)