Physics Internal Assessment
Aim
To conduct an experiment to investigate the effect of changing the mass of an object has on its acceleration when it is acted on by a constant force.
Hypothesis
I think that when the force is constant, the heavier the mass is the less acceleration whilst when the mass is lighter the most acceleration will occur.
Apparatus
- Pulley
- Bob mass
- Weights
- Fishing line
- Trolley
- GLX data logger
- Accelerometer
- Scissors
- Ruler
- Chocks
Method
- Attach the pulley to the end of a table
- Set up the accelerometer and the GLX data recorder
- Record the initial mass of the trolley
- Tie the fishing line to the end of the trolley and the other end to the hanging mass.
- Lay the line over the pulley, and align the trolley so it will run straight
- Place the accelerometer behind the trolley so it will record the acceleration by measuring the distance
- Have the trolley pulled back far enough to allow an accurate reading for the accelerometer and a person at the end to stop it falling from the table
- Run 5 trials per mass and record the values for acceleration
- Repeat steps 7-8 for 700g, 800g, 900g, 1000g, 1100g, 1200g, 1300g, 1400g, 1500g
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Peer Reviews
Here's what a star student thought of this essay
Quality of writing
The student's spelling and grammar are fine and they have followed convention by putting their independent variable on the x axis as they should, and the dependent variable on the y axis. Be careful to make sure you follow this convention. They have also made sure to repeat their results 5 times and work out an average, and clearly laid out their method before doing the experiment which is very helpful to ensure that the experiment goes smoothly. You don’t want to get to the point of doing the experiment and then not be sure what to do.
Level of analysis
The student shows appropriate analytical skills, they have first made a prediction based on theory and have in their conclusion tied their results to theory as is a good idea as it will help understanding and improve the quality of the coursework. They however should of made sure that the force was constant in their experiment, as you should make sure all variables other than your independent and dependent variables are controlled, and this varying force could make the experiment indicate incorrect results. After doing this they could also work out the force by working out the area under the graph, since F=ma, and the graph was m against a, the area will be the force.
Response to question
This is a good example of coursework, however it makes a few minor mistakes. The student has answered the question of how the mass of an object affects its acceleration very well. He has made a table which accurately shows that as the mass increases, the acceleration decreases. He also made a graph of his results which comes out as a straight line, showing that the result is linearly proportional. Be careful not to conclude it is directly proportional, as for it to be directly proportional it would have to go through the co-ordinate (0,0) which it does not. I would also of recommend that he could of worked out the gradient of his graph to see how much mass affects acceleration.
