# How Newton found Gravitational acceleration?

How Newton found Gravitational acceleration (g) of The Earth?

Can you describe the methods to find and prove it(g value)?

(may be describe both classical methods and modern methods)

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 did Newton have a stopwatch? Galileo had to use heartbeats, but I think Newton might have had a pendulum clock. – Ron Maimon Nov 2 '12 at 17:07 Actually I'm not sure that Newton measured $g$, or at least not to any special accuracy. He did do experiments with pendulums (penduli?) but I think it was to show that different materials gave the same period. – John Rennie Nov 2 '12 at 18:02 I suspect you are right, but then I am not sure when "g" was measured, or by whom. Galileo probably had a crappy measurement like "8.9 $\pm$ .6 (Galileo armspans) per (Galileo heartbeat)^2 ". Maybe it was Huygens. He was designing clocks, I think. – Ron Maimon Nov 2 '12 at 18:07