Guide with Forces, Motion, Newton's Laws & Momentum

[blaziken's_charizard]

I'd like guidelines on how to go about my assignment. I don't need the answers to the quetions, but rather an explanation on what should be in the answer. Below is the assignment, I need help with the bolded part of the quote and nothing else. Thanks a lot! The ictalized parts are what I'm done with.

Title:
Momentum

Aim:
To find the external force acting on a system

Theory
??

Materials and apparatus
A tennis ball
a stop watch with accuracy to 0.01s
a tape measure
and if possible a pool stick cut I am sure we will be able to substitute something.

Method.
1. Mark a straight line alone a floor in a relatively large room
2. Along that line, mark an x every 15cm
3. Place the ball at one end of the line and with a stick or something to that effect, push it with a suitable force
4. Time how long it takes to complete every 15cm interval until the ball stops
5. Repeat the above 4 more times
6. Place the data into the table below
7. Find the mass of the ball
8. Do calculations
9. Plot a graph – velocity against cumulative time

Results
Distance interval /m Exp I – t/s Exp 2 –t/s Exp 3 – t/s Exp 4 –t/s Exp 5 –t/s Ave t/s Velocity C. time
0.15
0.30
0.45
0.60
0.75
0.90
1.05
1.20
1.35



Discussion
What is a force?
Is there a force being applied here, if yes, what?
Explain the rationale of your method
Explain applications on knowing the force being applied
State sources of error, limitations and precautions
Explain what is going on in relation to Newton’s first and second law of motion – including momentum
Explain how this proves Aristotle’s law wrong
Any other business that you may see fit

Conclusion
The value of the retarding force acting on the tennis ball is _______N

 

[hage567]

What do you think? You didn't offer your opinion on what you think should be there. Is this the first time you've written a lab report? Those are pretty specific questions, so that makes it fairly straightforward. The point of the discussion is to explain the results in terms of the laws you are investigating (do they agree? why/why not?) and to show you understand what's going on. Just answer the questions and explain your reasoning. Read your textbook for relevant material. I'm sure you must have some ideas about your sources of error/limitations since you were the one taking the measurements. Explain what they are and what impact they may have had on your experiment.