course phy121
Class 1 Exp: Ball on an InclineI used the L-bracket in the lab kit along with the large steel ball, text book, three dominos and the long section of shelving.
I placed the L-bracket up against the text book to create a solid back stop. I then placed one end of the shelving on the bracket and the other on two of the dominos.
I marked the starting point on the shelving at 3mm from the end on the dominos, then the mid-point 14mm from the starting point twards the bracket end. This left me with roughly 13.5mm from the midpoint to the bracket. Its not perfect, but I don't believe that .5mm will make that big of a difference in my findings.
Procedure:
1. Place a domino on the incline at the Start mark.
2. Place the Large Steel Ball behind the domino.
3. Start the timer when you remove the domino from the rail.
4. click the mouse to set the interval as the ball passes the mid-mark.
5. Click again as the ball hits the bracket.
I ran three test runs and averaged the interval times to make my calculations with. Data is as follows:
Test # First Interval Second Interval Total Elapsed Time
1 .875 .309 1.184
2 .891 .406 1.297
3 .918 .375 1.293
Avg. .895 .363 1.258
vAve 15.64mm/sec 37.19mm/sec 21.86mm/sec
As you can see from my data, the vAve of the whole event is higher than the vAve of the First interval (first half) and lower than the vAve of the Second Interval (second half).
This shows that the ball had a higher vAve on the Second Interval than it did on the First Interval.
If you take the two interval vAve's and average them you get 21.42mm/sec, which is very close to the 21.86mm/sec you get from doing the calculations on the recorded times.
The ratio of the Second Interval:First Interval is 2.38:1, or the Second Interval is 2.38 times as fast as the First Interval.
Very good. Remember that you don't have to do anything that isn't assigned on the Assignments page; however you do get some extra credit for this. Given the quality of the work you are doing, you might not need it, but you've got it.