Graphical Methods Homework: Ranking Paths and Windows

[Lorek]

Homework Statement

I have no problem with mathematical formulas, but the graphical problems keep nailing me. For instance A figure which shows four paths along which objects move from a starting point to a final point, all in the same time interval. The paths pass over a grid of equally spaced straight lines. We have to rank the paths according the average velocity of the objects and the average speed of the objects, greatest first.

I can do it mathematically, but this whole graphical stuff is ridiculous. My prof just had a midterm with 3/5 of the questions using graphical methods, you can tell how well that went. Looks Like I'll be taking physics again next semester but I prefer to have these types of questions down before then. I've attached pictures of the diagrams.

The other question was Rank three windows according to a) the time it takes the cream tangerine to pass them, b) the average speed of the cream tangerine as it passes each window, and the other three windows c) the time it takes for them the cream tangerine to pass and d) the speed of the cream tangerine during the passage from greatest to least. Diagram #2 included.

Homework Equations

None

The Attempt at a Solution

 

[lewando]

Thanks for posting. I've spent more than a bit of time trying to determine if the juxtaposition of your stated difficulty with "graphical methods" and your blurry attachments constitute irony.

 

[lewando]

Sorry, was delayed a bit. Here’s my take on your situation: I don’t know anyone who doesn’t create some kind of graphical support (sketch, graph, etc) to help them visualize a physics problem. You need to be comfortable doing this and the best way I can suggest is to do about a gozillion word problems. Force yourself to draw a useful picture that depicts the known facts underlying realities of the problem. Eventually, you will get better at these “graphical method”-type problems.

Regarding the first attached image, are you aware of the distinction between average velocity and average speed?

For the second image (part a and c), think about the horizontal and vertical velocities. For the first 3 windows on the left, which component do you think applies? For the others, same question.

For parts b and d, do you have a sense of the speed of the particle at relative points on the curve? Where is it fastest? Where is it slowest? You can use logic to answer this question—no analysis needed.