If you want to make a pendulum clock from 500 g mass objects, and rope light pendulum swing by this anniversary, in 1 second fit. The rope must be long.
If you want to watch from the pendulum mass 500 grams lighter and rope by the pendulum is swinging around in the second one just has to have a length of rope.
If you want to make the pendulum from the object of mass 500 grams. String light and by the pendulum swing in this anniversary time 1 seconds. The rope will be longer to afford.