Sketching proportional and inversely proportional graphs (1 Viewer)

[Arithela]

What are the shapes of the two graphs? Are there other graphs that should be known in physics?

 

[Forbidden.]

What are the shapes of the two graphs? Are there other graphs that should be known in physics?

See the image below:

Proportional - As x becomes greater so does y.
Inversely proportional - As x becomes greater, y becomes smaller.

 

[xiao1985]

For inversely proportional, conventionally, may also have the y axis as 1/Y, so that the final graph is a straight line.

 

[Arithela]

i see so theres 3 types of graphs: straight line (proportional), hyperbola (inversely proportional) and parabola (?)

 

[me121]

If you say y is directly proportional to x, then that means that y∝x, hence y=kx where k is some constant. If you plot y=kx, (where k is const) you get a straight line, hence we say that the relationship is linear.

Remember that you can replace the proportional sign, ∝, with =k where k is const.

These (linear + hyperbolic) are the main two you need to know in HSC physics. Remember that the vertical stretching of the graphs will/can change depending on k.

 

[Arithela]

Thanks, but my teacher also mentioned a parabolic graph. What relationship is this shape used for?

 

[me121]

Thanks, but my teacher also mentioned a parabolic graph. What relationship is this shape used for?

You don't really need to know parabolic for HSC physics, but you should know it from year 10 maths. Its just y=x^2.