# How important is basic geometry for intro physics?

1. Jul 20, 2013

### QuantumCurt

Hey everyone, I was hoping to get some input on this question. I'm starting up an algebra based general physics sequence this fall, and I'm wondering how important basic geometry is going to be for it. I've never actually taken geometry, but I've done a decent amount of self study. I went back to school several years after high school. I never took geometry in high school, and in the interest of getting into calculus as quickly as possible, I self studied a little bit and placed out of geometry. I'm in trigonometry right now over summer sessions, and doing very well in it. Currently, I have about a 97% in the class, and I finished college algebra last semester with around a 96-97%. I'm starting calculus and algebra based physics in the fall, then going on to calc II and starting calc based physics in the spring.

Should I spend the few weeks between the end of summer classes and the start of fall semester self studying more geometry? I'm fairly comfortable with most of the area/volume type calculations, and the basic properties of angles and lines are no problem...but as far as proof writing and more complex figures/constructions go...I'm a bit weak. Will a solid knowledge of basic geometry be that important right away? If so, is it something that I could more or less pick up along the way?

2. Jul 20, 2013

### Staff: Mentor

That's probably all you'll need. Volumes and areas of circles, spheres, cylinders, etc.; sum of angles in a triangle is 180 degrees; things like that.

3. Jul 20, 2013

### QuarkCharmer

If your algebra and trig are good, this class will be no problem for you. The "geometry" involved is very intuitive. Any difficulty in the class will come from the physical principles, but that's what you are there to study in the first place.

If you still aren't sure about whether you should do any more preparation, just crack open the book that you will be using in the course and take a look. I think that Khanacademy.com has some videos on non-calculus based physics too that would be worth a watch.

4. Jul 20, 2013

### verty

You may from time to time see terms that you don't recognize. Perhaps look up these terms (if you don't know them) so you'll have seen them before: radius, diameter, circumference, chord, sector, segment, tangent, secant, perimeter, diagonal, bisector, perpendicular, midpoint, altitude, polygon, polyhedron, oblique, concave, convex, rectangle, square, parallelogram, cube, cone, cylinder, pyramid, prism, sphere. And then I suppose the shapes like pentagon, hexagon, up to 8 sides should be fine, and if you're still keen, the 5 platonic solids (just for fun).

5. Jul 20, 2013

### QuantumCurt

Thanks for the input. It sounds like I should be good for the most part. I might need to brush up on a few of those terms, and a few of the different measurement formulas. I'm sure I'll be looking for something to kill the time in between the end of summer classes and the start of fall semester though anyway. I'll have three whole weeks off, and I'm bound to get restless...lol

I want to start previewing the material for the physics course, but unfortunately I don't have the book yet. I get a lot of my books with financial aid money, and I can't get them until the week before classes start. I actually have the student solutions manual for the book already, so I have the solutions to a bunch of problems. Unfortunately, I don't have the problems from which the solutions came...lol

Another question- The algebra/trig based physics course I'm taking is a two course sequence, but I'm only taking the first one. The calc based sequence only requires the first course in the algebra based sequence as a prerequisite, so I'm going into the calc based after finishing this one. The first course mainly covers mechanics, thermodynamics, vibrations and waves, and sound. The second course covers electricity and magnetism, light and optics, and modern physics(quantum, relativity, elementary particles). Am I going to be at a disadvantage by not knowing the material from the second course before starting the calc based physics? I'm sure I'll end up self studying a lot of it over winter break in either case.

Thanks a lot for the input!

6. Jul 20, 2013

### QuarkCharmer

I don't think so.

I took Physics 1 (mechanics etc..) and Physics 2 (Electricity, Magnetism etc..) with calculus, without having taken ANY physics in my entire life. Nor did I take geometry. I didn't have any problem with any of it, and I'm not terribly intelligent or anything. If you are using one of the typical university physics books (Young/Freedman, Sears/Zem.., ...) then you will be fine.

You should really know your calculus though, and realize that these classes require many hours/week.

7. Jul 20, 2013

### QuantumCurt

That's what I kind of figured. I've always heard that the algebra based physics barely even functions as any kind of "real" preparation for calculus based physics, beyond developing general problem solving skills.

This is the book. Not sure how well regarded it is. The reviews are pretty mixed, trending to the negative side. https://www.amazon.com/Physics-Scie...&qid=1374369576&sr=8-1&keywords=9780716789642

Our physics classes are oriented towards engineering students more so than physics majors, but I imagine the lower level classes will be essentially the same. I'm in a community college currently, and engineering is one of the biggest draws here. I'll officially be a physics major starting in the fall, and I'll be the ONLY physics major in the school. There are plenty of engineering majors though.

8. Jul 20, 2013

### SteamKing

Staff Emeritus
9. Jul 20, 2013

### QuantumCurt

The geometry in that problem seems quite obvious to me honestly. The fact that the interior angles of a triangle sum to 180 degrees is pretty basic. If the three planets are all 1/3 of an orbit away from one another, it seems fairly obvious that they would form an equilateral triangle.

I've self studied a decent amount of geometry...enough to at least know the basics of it. My real shortcoming comes in proof writing. The properties of lines, angles, and basic shapes are straight forward though.

10. Jul 20, 2013

### WannabeNewton

If you know what a transversal is and what the properties of angles formed by parallel lines intersecting tranversals are (on top of the basics) then just make sure you got your trig down and you'll be fine.

11. Jul 20, 2013

### QuantumCurt

Thanks for the tip. Transversals and their corresponding angles are easy stuff. I guess I'll just focus in reviewing some of the formulas for area and volume. I know all of the basic, standard shapes...but I should probably review some of the more uncommon ones. I need to review some of the volume and surface area formulas for solids too.

12. Jul 21, 2013

### Theorem.

You know... It couldn't hurt to just learn more geometry anyways : ) It is very useful and even when it is not, it could help develop better problem solving skills which is incredibly important.

13. Jul 21, 2013

### QuantumCurt

Very true. It's a subject that I still plan on self studying more in my free time. I skipped it in the interest of saving time, because it was more important to get into calculus as soon as possible. I wish I hadn't needed to skip it though, because it's a topic that I find really interesting. I'll be taking more advanced geometry classes(differential geometry) sometime down the line I'm sure, so it would be a good idea to get a solid grounding in it now.

One of my friends was in geometry last semester, and I bought her textbook and study guide off of her at the end of the semester. This is the book I have, along with the accompanying workbook/study guide and solutions manual. https://www.amazon.com/McDougal-Lit...=UTF8&qid=1374390879&sr=8-2&keywords=geometry

Anyone have any other recommendations for good geometry self study tools? I've watched basically every video on geometry on the Khan Academy site. I need some tools to learn more about proof writing and whatnot. This textbook is very heavily proof oriented though.