Basketboll som faller
By MichaelMaggs (Own work) [CC-BY-SA-3.0], via Wikimedia Commons
Beskrivning från källan:
English: An initially-stationary object which is allowed to fall freely under gravity drops a distance which is proportional to the square of the elapsed time. This image, spanning half a second, was captured with a stroboscopic flash at 20 flashes per second. During the first 1/20th of a second the ball drops one unit of distance (here, a unit is about 12 mm); by 2/20ths it has dropped at total of 4 units; by 3/20ths, 9 units and so on.
To take the picture, the ball – about the size of a tennis ball – was suspended by a short length of black thread and was released as the shutter was opened and the flash triggered. The shutter remained open for the whole of the half-second period, during which time the flash fired multiple times to capture the ball at 1/20 second intervals.