The Kinetic Energy - Sample Essay

The aim of this piece of work is to investigate the factors that affect how fast a marble/ball bearing travels once it has travelled down the curtain rail. Factors: There are 5 main factors that affect the speed of the marble/ball bearing once it hits the ground after travelling down a curtain rail.  The surface may well change as it changes from the curtain rail to the floor. It could be smoother or rougher. If it’s rougher the ball will slow down its speed quite quick due to friction whereas if it were smoother it would travel a further distance because it will have a higher speed.

It will be easier to pass over the surface if it is smooth. The marble/ball bearing itself could be of importance. Its weight and diameter could affect the speed. The bigger and heavier the ball the shorter the distance it will travel because the speed will be slower than with a small light ball which will travel faster.  Another point would be the height of the beginning of the track from the floor. The higher the track the faster the ball will travel when it comes off the end. However, if the track is very close to the floor the marble/ball bearing will not get very far due to low speed.

This is the most important factor because it more or less determines the speed the marble/ball bearing is going to travel and how far it is going to travel.  Air resistance may play a minor part in the speed of the marble/ball bearing. There is nearly always air resistance therefore it could slow the ball down a tiny fraction.  The length of the track could play a large part. The longer the track the faster the marble/ball bearing has to go to get a longer distance. If it is a short track the ball bearing will be at a higher speed as it reaches the floor because it hasn’t had much time to slow down.

Fair Test For this to be a fair test everything has to be done equally. If you decide to choose the height of the track to be the most influential factor then that is the only thing we must vary. The same ball must be used for each test. If not the size of the ball could speed up or slow down the average speed of the same ball. The same track must be used each time. If not the different tracks could have a rougher or smoother surface from each other and this may affect the speed of the marble/ball bearing once reached the floor.

Before timing each test the distance measured and timed at the end of the curtain rail must be the same each time you do it. It must also be done in the same place to make sure that the air resistance is the same. All these aspects must be undergone for it to be a successful experiment. Predication and Scientific Knowledge My prediction is that the higher the curtain rail at the beginning the faster the marble/ball bearing will travel along the floor and the further it will travel along the floor. The lower the curtain at the beginning the slower the ball will travel because there isn’t as much gravity forcing it along the rail.

On a rollercoaster for example there is Gravitational Potential Energy at the top of a drop which converts into Kinetic Energy when it reaches the bottom of the drop and slows down. Gravitational = mass x height x gravitational Field Strength Potential Energy Kinetic Energy = 1/2 x mass x speed 2 There is also transferred into heat energy and sound energy. But then if we forget about the laws of friction and the energy given off from friction both Gravitational Potential Energy and Kinetic can be equal. If the height changes on one the velocity will changes to be equal as well. Method:

To find the speed of the marble/ball bearing travelling along the floor it will have to be timed over a certain distance. The distance should be accurate and reasonable to be able to get a good time in. It should be 2 or 3 metres. Preferably 3. It should be measured from five heights and timed on each one. This should be done at least 3 times to get a good average and set of results that you can work with. The range of heights need to be equally set apart. In this case it should be 10cm, 20cm, 30cm, 40cm, and 50cm. The times need to be recorded from when the ball leaves the curtain rail to where the 3 metres is finished.

All results must be recorded. Preliminary Experiment: In our preliminary experiment we found that Gravitational Potential Energy converts into Kinetic Energy once at the bottom. The marble/ball bearing gradually slowed down as it travelled along the floor. Another thing on the preliminary experiments was that once the ball had fell down the bottom and up the other side of the curtain rail and reversed in couldn’t reach the same height as the start because the marble/ball bearing has lost most of its Gravitational Potential Energy and therefore can’t turn it into Kinetic Energy anymore. The Obtaining.