# Pendulum question

#### Thomas Nguyen

##### New member

I can't find the formula to represent the relationship between l and P in question b/,

#### Harry_the_cat

##### Senior Member
Have you plotted the points? Desmos is a graphing program you can download. Or you could use a graphics calculator. Or you could use Excel.

#### Subhotosh Khan

##### Super Moderator
Staff member
View attachment 12740

I can't find the formula to represent the relationship between l and P in question b/,
You are being asked to derive that formula by investigating the plotted graph from the given set of data.

#### Thomas Nguyen

##### New member
Have you plotted the points? Desmos is a graphing program you can download. Or you could use a graphics calculator. Or you could use Excel.
I've tried it as well, got all the points. i tried y=0.2√x an it kinda fits into the points

#### Thomas Nguyen

##### New member
You are being asked to derive that formula by investigating the plotted graph from the given set of data.
like coming up with a formula? i got y=0.2√x estimated?

#### Subhotosh Khan

##### Super Moderator
Staff member
like coming up with a formula? i got y=0.2√x estimated?
Now put that (y=0.2 * √x) in terms of 'l' and 'P'

#### Thomas Nguyen

##### New member
Now put that (y=0.2 * √x) in terms of 'l' and 'P'
Can you have a look at c) ii) please. I know that the similarity is both are in the form of y=a√x . But I dont know how to put the words to describe the differences

#### Subhotosh Khan

##### Super Moderator
Staff member
Please state Galileo's equation (formula) for simple pendulum.