Graphs (1 Viewer)

[velox]

General method so you can apply it.

Place your equation in the form
y=mx+b
From your graph T² is your y
l is your x

T²=ml

Rearrange your original formula into this form (square it) and you should come up with

m=_________/___________

If you can't work out m then post again.

Im still lost. My equation for the line was y = 1.9336x + 0.0424. What do i do then? I know you said let T² be the y, but i have no values for either... I end up getting (1.976 = 1.9336 * m) which is completely wrong as the acceleration due to gravity would then equal 1.02ms^-2 Arggh, so frustrating being dumb =/

 

[helper]

For a Graph there are three main significant parts for physics:
1. The Slope
2. The Area under the graph
3. The intercept

When you graph something it is important to determine what these three things mean.

1. The slope is determined by looking at the equation.

2. The area is determined by looking at the product of the two axis.
Eg A graph of Force versus Time.
Product = Ft
Area = Ft = Impulse

3. The intercept, determined by looking at the equation. It can be significant if there is an intercept in an equation or if there isn't may represent a systematic error in your measurements.
Eg. A graph of velocity versus time
y=mx+b
v=mt+b
Compare to v=u+at
Intercept = initial velocity
Slope = acceleration


So back to your problem.

y=mx+b
From your graph T² is your y
l is your x

T²=ml

Equation for pendulum after squaring

T²=4pi²l/g

Comparing to your equation

m = 4 pi²/g

Rearrange to solve for g

 

[helper]

Comparing
T²=ml (from y=mx+b) and T²=4pi²l/g (from equation)

ml=4pi²l/g

Cancel l

m=4pi²/g

 

[velox]

I substituted the values back in and got g to equal 20.41.........Anything thats wrong?

 

[helper]

What data are you now using?

If you use your original and force the intercept = 0, then the slope is 4.11, and this results in an answer of g=9.6

 

[velox]

i think i know what may have gone wrong, i was using a graph of period vs. length of the pendulum not period ²
Thanks for ur help helper, ill see if i get the correct answer now.

 

[velox]

damn excel wont graph it =/ Is there anything else i can use to graph it?

 

[helper]

In excel when you add the trendline, there is the option of forcing X=0 for the intercept.
You can justify this in your discussion by saying the relationship must go through 0,0

 

[velox]

yep got it now, finally, thanks again helper. Got the value of 'g' to be 9.87