An investigation into the energy in an elastic band and the amount it is stretched in comparison with the energy stored or lost in the process of doing so.

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PHYSICS COURSEWORK

CATAPULT EXPERIMENT

Introduction

This coursework is an investigation into the energy in an elastic band and the amount it is stretched in comparison with the energy stored or lost in the process of doing so.

Using the formula Energy (or force) (J) = Force (N) x distance (m)

Work is defined as the application of a force to an object that results in the object moving. When work is done to an object then it is turned into kinetic or potential energy. For example, if you were to stretch an elastic band and put a round rock into the end of it, then the rock can fire from the elastic band like a catapult. The elastic band has potential energy that was transferred from energy from your muscles when you pulled it back which is chemical energy.

Using a newton ruler we stretched the rubber band back. Between each measurement we stretched the elastic band back 2 newtons on the newton metre each time. Then using the rubber band we catapulted the 100g weight. After the 100g weight had been ‘catapulted’ we then went to measure the distance it had travelled from the stool using a metre ruler.

Fair experiment

In order to get a fair experiment I will:

  • Use a metre rule (and line it up with the vertical lines on the floor) to get precise, accurate measurements
  • Not move the stool as that will effect the measurements
  • Repeat the experiment at lest 3 times to ensure at least two results are accurate
  • Use the same 100g weight for each experiment
  • Attempt to use the same release method (on the elastic band) each time
  • Do the experiment on the same section of the floor each time so there will be no variation in the amount of friction
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The variables that I will change in my experiment is the force, my range of force I will be using is from 2N to 12N of force.

Prediction

My prediction is the further you pull back the elastic band, the more distance the mass will travel across the floor. As the elastic band is stretched the elastic band has potential energy stored. As you release it the force is turned to kinetic energy on the weight.

The weight is slowed slightly by friction from the floor so the results will not be as accurate. To work out ...

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