# Understanding of projectiles from physics

1. Aug 22, 2009

### Mentallic

I was unfortunate enough to have sports on the days of my mechanics classes so I've basically missed most if not all of the basics of this topic, and a test is coming up shortly.

What I need is a crash course on this topic. Extension 2 mathematics (Australian high school) on mechanics (projectiles in resistive mediums, pendulums etc.).

I already have a basic understanding of projectiles from physics and extension 1 maths, such as the horizontal and vertical components, displacement, velocity and acceleration etc.

I know a few formulas thus far such as:

$$w=\frac{d\theta}{dt}$$

$$v=rw$$

$$a=\frac{v^2}{r}$$

If you guys have any tips on the basic procedures required to solve each type of question, I would really appreciate it. I'll also be asking questions in the homework forum, without much attempt, because I'm seriously lost on all this.

2. Aug 22, 2009

### Gib Z

Re: Mechanics

Wow I've seen you on the forums for so long and didn't even realize! I'm doing Ext2 Maths as well, I just had my trial this week!

Well if you have a couple of days, you can still cover it all in time. Start with resisted motion. The key is knowing the relations between the variables - time, position, velocity and acceleration.

You need to know the three forms to express acceleration:

$$a = \frac{dv}{dt} = v \frac{dv}{dx} = \frac{1}{2} \frac{dv}{dx}$$.
These allow to to describe the motion as functions of position as well as time. The key is to read the question carefully and express the information you have in the form that relates the variables know to the variables required.

If you want, get one of your textbooks and I'll help you though some examples and questions.

3. Aug 22, 2009

### Mentallic

Re: Mechanics

Oh wow you're doing ext2 maths? Your profile makes it seem like you're well into university already. (linear algebra, real and complex analysis?), I admire your ability to go ahead enough so that you can enjoy the topic. I attempted to learn linear algebra through the MIT lectures on youtube once... it was horrific by the 3rd lecture! There's no way one can understand everything just through lectures.

Thanks I'll keep those equations in mind, and I think you meant $$a=\frac{1}{2}\frac{d(v^2)}{dx}$$

I'll post links in here to the homework section, for ease.

4. Aug 22, 2009

### Mentallic

Last edited by a moderator: Apr 24, 2017