if a 200-g mass is placed at the 20-cm mark (30 cm from the fulcrum), at what mark should a 500-g mass be placed so that the system balances?

1 answer

The fulcurm is at 50cm, as I understand.

Summing moments about the 50 cm mark. Clockwise moments are positive.

200g*30-500*L=0
L= 2/5 * 30

so the mark will be 50cm+ L or at the 62cm mark.