In your picture of the collision, there were a number of individual pucks shown
ID: 1770808 • Letter: I
Question
In your picture of the collision, there were a number of individual pucks shown both leading up to the collision and leading away from the collision. Technically we only needed two puck pictures per vector, to figure out what the time interval is form your data. Explain how using only two puck pictures can be both a bad idea and a good idea as long as the puck pictures used are all close to the actual collision. (Hints: This is a precision vs. accuracy question. Remember that all we care about is whether momentum is conserved before and after the collision itself, not necessarily during the time leading up to the collision or during the time after the collision. So measuring .....might improve the fractional error, but it means more momentum lost to ......)
Explanation / Answer
We know that the momentum of the system remains conserved, so we can calculate the velocities and after that we can find out the time interval for each puck.
We could have used a single pair for the calculation of time interval but this would have given us just an actual value. An accurate value is the close value between a measured and a true or accepeted value.
We certainly need precision here. So we will take a number of puck pairs to determine the precise value of time interval, and that is how we can find the consistent value by the independent measurement of a quantity from a number of pair of pucks.