How does changing the force applied on the elastic band affect the distance travelled by the margarine tub? Preliminary investigation- Aim- To determine the range of forces to be used and to decide on the values of the other variables. Shape of margarine tub: Bertolli Mass of margarine tub: 35. 6g Surface area of margarine tub: 84cmi?? Surface area of front of margarine tub: 47cmi?? Number of 10g weights used: 2 Floor surface used: Lino Distance travelled at 2N force: 49cm Distance travelled at 10N force: 263. 5cm Range of forces used: 2-10N Why I used this range.
I decided to use the range of 2-10N to minimise my chance of getting anomalous results. For example, if my range was between 1-5N then I would be carrying out the experiment for every Newton force applied to the elastic band, therefore the results will be too close to each other and might overlap, these results would be considered un-useful and this would mean I would have to repeat the experiment until I got generated results that are deemed reliable. For me to not generate unwanted anomalous results, the range used was made bigger. I used the forces, 2N, 4N,6N,8N, and, 10N to generate my final results. Number of 10g weighs-
In addition, weights were used, which I stuck down so that the force from the elastic band would not change the direction of the margarine tub and so that it travelled in a straight line. If no weights had been used, we would expect the tub to change direction and possibly jump due to the force applied and therefore this result would be deemed anomalous. Background knowledge- The forces on the tub at the start are equal and the margarine tub is therefore stationary. The elastic band is pulled and released, and as a result, when it comes into contact with the tub, the tub is pushed forwards by the force and accelerates.
It then stops a distance away from the elastic band. The law of energy states that, ‘energy cannot be made or destroyed but it can be changed from one form into another or transferred from one place to another’. Tension is put on the elastic band when it is pulled, and by virtue, the elastic band is provided with elastic potential energy, ready to be released when it is liberated. When it is released, as the law stated, the elastic potential energy is changed into kinetic energy when it comes into contact with the margarine tub and it therefore moves due to this transfer of energy from the elastic band.
However, there will be forces working against the tub to try and slow it down and make it stop. The main force is friction which will occur between the base of the tub and the surface of the Lino. As a result, some of the kinetic energy transferred on the tub will be changed to heat energy as the temperature between the surfaces increase. Similarly, air resistance will transfer some of the kinetic energy left into more heat energy as the air particles collide with the front of the margarine tub.
This process will carry on to the point where all the kinetic energy has been transferred or changed and the margarine tub has no more kinetic energy left. As a result, the tub will decelerate to the point where it stops. When the elastic band is pulled due to the force applied by the hand, when it is released, the elastic band will come into contact with the stationary tub and the force will push the tub and cause it to accelerate. Newton’s second law clearly states that; a force exerted on an object of mass (M) will cause the object to accelerate (A).
This is illustrated in the following formula: F= M X A For an object to accelerate, a force has to be applied for it to move. The elastic band is providing the force for the tub and as a result, it accelerates. Prediction- As the force applied on the elastic band increases, the distance travelled by the tub will become greater. Linking prediction with theory- The greater the force applied on the tub, the greater the tension on the elastic band and therefore there is more elastic potential energy transferred so more kinetic energy drives the tub forward and it goes a greater distance.
Basic method- To prove my prediction correct, I will conduct a fair test where I will be testing and measuring how far the margarine tub travels depending on the tension and force applied on the elastic band. I will generate 3 results for each force and they have to travel within 5cm distance of each other. To aid me in this investigation I will require the following apparatus: Step 1- Step 2- Step 3- Step 4- Step 5- Step 6- Step 7- Step 8- Step 9- Step 10- Step 11- Write down the results obtained in a table and generate averages.