Testing Hooke?s Law Essay, Research Paper
Hooke?s Law is when forces are applied to a solid object and
it can result in extension or compression.?
Hooke?s Law is able to predict how a spring (or other stretchable
object) would behave when force is applied to it.I aim to show how much force (N) strips of supermarket
plastic bags will take before it reaches its elastic limit and whether the
width of the strips can alter the results.I am going to do a simple experiment that involves cutting a
plastic bag into strips which are all different sizes, 25cm x 5cm, 25cm x 10 cm
and 25cm x 15cm.? Then I am going to add 100g weights to the length of plastic
bag until I reach its elastic limit.? After each 100g has been added I am going to measure the new
length of the plastic bag strip. I will then note the difference between the length of the
strip at the start of the experiment and the length at the end in order to see
what permanent damage has been done.? To make it a fair test I will use the same types of plastic
bags and make sure that they are always the same length.? I will also try to gently add the weight so that the force
with which it landed does not alter the results.The most important factors are that I make sure that it is a
fair test and that I take accurate measurements.I will need to take measurements in centimetres after every
100g is added.The reason I should obtain accurate results is because I
know that the strip should stretch at equal amounts until the strips have been
stretched beyond their elastic limit. I will have to be careful to make sure that if the strip of
plastic bag breaks the falling weight could not be a danger to anyone.? I
will be taking minor precautions and shall not be adding ludicrous amounts of
weight onto the beam.
The measurements that I will be taking must be done as fairly as possible or
the results shall not be accurate. ?
The equipment that I will use should be checked to make sure that there is
nothing wrong with it; I will make sure that I use the best equipment available
to me. ?Diagram Equipment list Clamp and Stand Weights (In different
proportions) A measuring apparatus
(Ruler) Plastic bag strip Prediction I believe that the different widths will slightly alter the
results.? This is because the force
remains equal but there are more molecules contained in a larger surface (wider
strip) than there are in a smaller one.?
The 25cm x 5cm length of plastic bag will reach its elastic
limit earlier than either of the other too.The 25cm x 15cm length should be able to withstand the
largest amount of weight before reaching its elastic limit.The results should remain consistent and increase in even
amounts until the chosen strip reaches its elastic limit.Results ??????????? 25cm
x 5cm???????????????? 25cm x 10cm?????????????? 25cm x 15cm Force applied (grams) Length increase (Cm) Length increase (Cm) Length increase (Cm) 100 30 30 30 200 30 30 30 300 31 31 31 400 31 31 31 500 32 32 32 600 32 32 32 700 33 33 33 800 35 33 33 900 42 34 34 1000 43 34 34 1100 Snapped 37 35 1200 38 35 1300 42 36 1400 48 36 1500 Snapped 37 1600 41 1700 43 1800 45 1900 49 2000 Snapped ?? Conclusion My prediction was correct.?
The difference in width did affect the elastic point on the plastic bag
strips.? Due to having foreknowledge of Hooke?s Law it was easy to
roughly predict what the results were going to be.? Also being aware of the movement in molecules that are found
in solids was helpful.? This helped me
come to the conclusion that due to the amount of pressure on certain parts of
the strip a wider strip would be able to withstand more pulling from the
weights.? Algebraic formulae Force???? >???
Strip Strip will stretch by ?X? amount Double force = ?2X?So?F > S S x X 2F = 2XEvaluation The experiment managed to produce some decent, accurate
results so that I was able to produce a graph and come to a good
conclusion.? All of my results seemed to be very accurate.? They all followed a pattern until they reached
the elastic point.? After they had hit the elastic point the results became
harder to record because they were so varied.?
Also some of the measurements could have been slightly inaccurate
because I was using a 30cm ruler.To make sure that all my results were accurate I would have
to have more time and be able to repeat them again.