Verified answer

T^2 = 4pi^2 [L/g]

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if you plot length (L) { x-axis} and time period (T){y-axis}, you will get the curve called parabola

Y^2 = k X

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keep in mind that you measure time (t) for 5 oscillations, and T = t/5 = time period

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if you plot between Y = T^2 and X = L

then you will get a STRAIGHT LINE

Y = m X

and plot will be nick-named T^2 vs L plot

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eve if you interchange length to y-axis, nature of curves will not only terminology will change like X^2 = k Y (again parabola)

OR X = m Y again straight line

length=spatial

t squared

so if you have x/t you have velocity

if you have x/t/t you have acceleration.

it would be a graph of acceleration