Investigating the depression of a ruler when force is applied.

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Investigating the depression of a ruler when force is applied

Investigation: Measuring the depression of a ruler when force is acted upon it and when the length of overhang is altered.


First of all it was important before starting anything that the environment where the experiment was taking place was a safe one and that I was not in any danger whilst doing my investigation. I will make sure that the desk is clear with only the required apparatus present and also make sure that no more weight than 6N is put on the ruler otherwise it might snap and a splinter could come up into my eye.

There are three independent variables in this experiment. These are the over-hang of the ruler, the mass added to the ruler and where the mass is positioned on the ruler. I will be investigating two of these independent variables, which are the alteration in overhang and the mass added to the end of the ruler. These will then produce a Dependant variable. This is the amount the ruler bends. For this experiment I will set up a one-meter ruler lying horizontally off the side of the work desk with a block of wood on top of it and a G Clamp holding it in place so it does not move. I will then add individual weights of 1 Newton to a piece of string hanging on the end of the overhanging ruler. I will measure the distance that the ruler has bent by using another ruler lying vertically from the floor held by a boss and clamp stand. This is so that the vertical ruler is straight otherwise the results will be inaccurate as the ruler is a longer length up to the point than if the ruler is vertical. So I get an accurate result, I will stick a pin on the end of the horizontal ruler with plasticine so it points directly to the value on the vertical ruler, telling me how much it has bent. I must remember to crouch down and look at the measurement exactly vertically otherwise parallax will be the consequence, which will give me an inaccurate value. After the first test of adding and reducing the mass at the end of the ruler, I will then try changing the over hang of the ruler and compare results with the other results and see what relation I can find between the two sets of data.

 A similar experiment was done before this one where I measured the stretch of a spring when a force was applied on it. We found that this experiment did obeyed Hook's Law, and that the stretch of the spring was proportional to the force applied.

The equipment needed are two rulers, one for the mass to be added to and the second to measure how much the ruler bends. I will also need a G Clamp and a block of wood to keep the horizontal ruler clamped firmly to the desk and a boss and clamp to keep the vertical ruler in place. Also I will need string to hang the weights from, Newton weights that can be added/taken off individually and a pin with plasticine to attach to the end of the over hanging ruler.

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I predict that the more weight put on the greater the depression of the ruler. Also, the more rulers over hang, even more depression of the ruler will occur. This is because there is more weight on the end of the ruler and therefore a greater gravitational force pulling down on the ruler. In scientific terms, I predict that the weight in Newtons will be proportional to the bend in the ruler. I predict this because although this investigation is bending a ruler not stretching it like Hookes law, it will have a similarity to Hooke's first law. Also, like ...

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