Can someone clarify some things for me?

1. Sep 16, 2011

matt@USA

I don't know if I am just looking too much into the problems or what, but I am having a very hard time determining what is what in the problems. I am not confident on what I pick as Vnaught, V, x, y, etc .... Will someone please help?
I will tell you how I determine it, and you can correct me.

x=where it lies on the x axis?
y=where it lies on the y axis? ... Both of these are determined by me? Correct?

So is V the velocity of the object? And what is Vnaught?

These are all pertaining to 2D equations.

2. Sep 16, 2011

QuarkCharmer

Naught is usually the initial value of something. If you have a position graph then you could say that x naught is the starting position of the object. You see subscripts used a great deal. i usually denotes an initial value as well, f usually means the final value. Aside from that everything else is pretty descriptive. When you are dealing with 2+d problems, you might see subscripts of x and y to let you know which component it is. Say you have a vector r, they might say that $a_{rx}$ is the acceleration of the x component of the r vector and so on.

Last edited: Sep 16, 2011
3. Sep 16, 2011

cepheid

Staff Emeritus
Yes, x and y are positions, measured along their respective coordinate axes.

v is velocity. In general it varies with time (i.e., pick a time t, and you'll get a specific value for v).

v0 is initial velocity (i.e. velocity at t = 0).

4. Sep 16, 2011

matt@USA

So what is V?

5. Sep 16, 2011

PeterO

In the context you have provided, V would be the velocity at the time to are dealing with.

Vo is the initial velocity. V is the velocity later.

eg: you might want to know "if a stone is thrown vertically down from the top of a 30m tower with a velocity of 2 ms-1, how fast will it be travelling just before it hits the ground -[take g=10].

everything is happening downwards, so let down be positive.

Vo = 2.0
a = 10
x = 30
V = ??

Best formula to use would be

V2 = Vo2 + 2as

V2 = 4 + 2x10x30 = 604

so V = 24.6