Method for question 3: I will start up with the metal iron side first (dun have any special reason, just feel like it). Set up the apparatus like the above diagram (see the plan), with a 100g mass on the block (to see how much force we need to move 100g by using the metal iron block). Make two tables to record two kinds of block materials (the force needed for each material block will be different as my hypothesis said). Gently pull on the force meter until the block is moving at steady speed (it has to be constant speed because we want to find out the more accurate force). While this happens, take a reading on the force meter and record in the table (therefore, I can analysis my results and draw graphs, do calculations, etc). Repeat the step several times, each time add another 100g mass to the pile on the block until I have all the forces for 10 different forces. Finally, record all the reading in the table. Repeat the above steps again, but this time use the cork side (to see if different surfaces/materials can affect the force needed).
Table for question 1:
Table for question 3:
P.S. The table in question 1 cannot compare with the table in question 3. This is because although all of those three blocks have the same thickness, they dun have the same weight. The block in questions is much heavier than the one in question 1. Question 1 and question 3 are totally independent to each other.
Analysis: Please see the attach pages for the graphs. From the first graph, we can obviously see that the force is increasing at constant values (0.3 Newton) as more masses are put on. From the second graph, we can clearly see that we need more force to move the masses on the cork block than the masses on the metal iron block. The force needed for metal iron block to move masses is increasing at constant values (0.2 Newton) while the force needed for cork block to move masses is increasing at constant values (0.5 Newton).
Conclusion: The results proved that my hypothesis was right. The strength of frictional force depends on the nature of the surfaces that are in contact and the force pushing them together. This force is usually related to the weight of the object or objects. More force will be needed to move more mass and different material surfaces will affect the friction/force. Smoother materials will create less friction while rougher materials will create more friction. (Please see the research on the other page to find out more information about the force created by each material surface.
Evaluation:
There are only one thing went wrong during the experiment. Some of the force meter is not accurate, because the pointer does not go back to zero, therefore, there will be some error occurred. To overcome that problem, I find a better force meter, which the pointer goes back to zero. Everything else went quite well, there were just one or two odd results made. What I did with the odd results is I compared the odd results to the normal results and found out what was wrong, and then changed it. I could improve accuracy by doing more trials; unfortunately, I did not have much time to do more trials. I made my own question 4, which I later found that it is too hard for me to do it. “In cases involving fluid friction, the force depends upon the shape and speed of an object as it moves through air, water, or other fluid”. I wanted to find out more about fluid friction and see the shape and speed of an object will affect the friction or not. I learnt more about friction during the experiment, how friction works, how does the material affect the force…etc.
Research:
