# Homework Help: Some random questions on homework.

1. Jan 25, 2005

### Zoe

I've got a few questions on a "semester review" that I'm not understanding fully, and can't find the answers or explanations in my book. I'd be incredibly grateful if somebody could explain any or all of them to me!

For a lot of them, I have an idea of the answer but I'd like to know the reasoning behind it. Some is because I just haven't dealt with it for a while, and so might just need a refresher to be able to answer correctly.

Why does a baseball player follow through when he hits the ball? (I know this has something to do with impact/impulse, but I'm not quite sure.)

A ladybug on the inside of a spinning wheel will experience a force like gravity. (True/False question. I'm thinking true - I remember talking about spinning spaceships creating a gravity effect. How does this work?)

To increase rotational inertia, a tightrope walker carries a long stick. (True/False.)

If you squeeze a loaf of bread, its mass and density will increase. (True/False. I know density will increase, not sure about mass.)

A cannonball is fired at some angle and moves 10 meters horizontally in 1 second. How far will it move in the next second? (...no idea.)

A car is moving in a circle at a constant speed. What is the net force acting on it?

A car accelerates from rest to 20m/s in 10 seconds. It weighs 10,000 Newtons. What is the force on the car?

Essay Question:
Describe how Newton's three laws can be applied to a rubber ball that bounces off the wall of a no-gravity spaceship. Where is momentum conserved? (I can get through the law of inertia and action and reaction, but I'm not sure how force and acceleration applies to this. And again, I don't remember what momentum "being conserved" is. Sorry!)

Thank you so much for any help. :)

Last edited: Jan 25, 2005
2. Jan 25, 2005

### plusaf

i hope this helps.
just for calibration, what grade are you in?
thanks!
+af

3. Jan 26, 2005

### Zoe

Thanks very much, that did helped a bunch! When you said "that classic equation that relates force to mass and acceleration," I was thinking "What?...oh DUH!" ;) Oh, and I'm in 10th grade.

Thanks again!

4. Feb 1, 2005

### plusaf

A pleasure to help. i hope some of the other suggestions helped, too. i'm one of those obnoxious kinds of "teachers" who thinks that the best kind of learning happens when the student gets the "AHA!" on their own, after maybe some gentle nudging in the "right direction."

another hint which might help you is to get yourself familiar with as many of the basic physics equations as you can.... then, when faced with a problem, see if you can list, from the description in the problem, which factors are provided.... if, in that example, you're given mass and acceleration, even before they ask for the force, you might be thinking... M, A.... M, A... ah! f=ma...... and guess what they're asking for... f! practically done deal.

one other thing, that i think virtually nobody is going to tell a tenth-grader, is to take a look at yourself and how you learn things best. do you visualize a picture of a problem (or a solution) as you're working on it or learning the basic theory, or do you "talk yourself through it" with the little voice in your head describing the process in words.

the difference is called "visual" versus "auditory" learning and memory. if you tend to use one of the two "styles" more comfortably, focus on using that for learning the theory and creating the solution.

i'm very "visual". i can't solve a problem well if i can't picture what's happening in the problem, in my head. i learned my multiplication tables by memorizing what the answers "look like", and since i was about your age until now, i can still multiply from 1*1 to 9*12 in my head. i just "see the answer" without doing the math in my head, so to speak. same for addition.

if you can figure out a technique that helps, use it! it makes whatever you're learning more fun, too...... wish i'd figured out something like that for social studies back then........ :rofl: