Practical: Measuring g

You can measure g by using an electronic timer and motion sensor or the apparatus shown belowA ball is released from rest from an electromagnet.
This uses s = ½ a t ²since u = 0 => ut = 0
You can also use a video clip or multi-flash photography of a ball falling vertically against a metre rule.The ball speeds up as it falls.A graph of s against t² should be plotted and should be a straight line.

y	=	m x	+	c
s	=	½ a t 2	+	ut

gradient = ½ a