Physics Graph

[dayav07]

for school we had to investigate the relationship between the static friction force and the normal reaction force acting on an object.

So we have 2 variables, normal force and the static friction, one divided by the other should give a constant (k) which will give the graph a straight line.

What i'm not sure about is what to label the x axis and what to label the y axis. i heard my teacher saying something about the dependent variable being on the x axis but i'm not too sure

some help please

 

[Gadget Man]

Either way it will still be a straight line. I would say normal force on x, because static friction (dependent) only comes into play with a normal force (independent).

 

[scotty777]

Hmmm. well, you know that you can make any graph into a straight line graph right? Like if I had the graph y=x^2, you can right that as, log(y)=2log(x) where you have a y, an x, and your gradient (m) or 2 in this case.

But in this case, I don't actually see how dividing static friction by dynamic (normal friction) will yield a constant. This is because static friction is the friction in which when you apply a force on an object, the object won't move until you apply enough force (as though the object is stuck to the surface it's on), but when you get the object moving, the force needed to keep it going drops substantially (basically, once you break an object free from it's static friction, you'll need less force to keep it moving/accelerating).

Further more, y is your dependent variable (to prove this, you can write a graph like this: f(x)=x^2... f(x) is dependent on the x value, therefore the x-axis is your independent variable. you must remember this format because you actually lose marks for wrong interpretation of data!).

But remember, if all else fails, copy your friend

 

[dayav07]

hehe im still confused... so which one goes where ? (G)

 

[scotty777]

Ok:

INDEPENDENT VARIABLE: this goes along the x-axis. The independent variable basically is the variable that isn't influenced by anything, but it influences the results. For eg: Time... the experiment doesn't change times results , but time changes the experiments results.

DEPENDENT VARIABLE: The goes along the y-axis. The dependent is influenced by the independent variable, meaning that what ever the independent variable does, the dependent variable changes.

So is you want a straight line graph you will need:

a Y (or f(x)), this is the dependent variable, so you need a dependent variable.

an X, this is the independent variable, so you need an independent variable.

a gradient- this is the constant that is multiplied by the x coordinates to get y values.

and a y-intercept, this finished off your graph.

you need all of those to draw a correct graph. have fun, and pay attention in class.

 

[dayav07]

so in this case the normal force is the dependant? so that will go non the y axis and the static friction on the x axis?