An essentially weightless shovel is 120 cm long. Someone holds it horizontally, supporting it with his left hand at the shovel’s center of gravity and his right hand 80.0 cm to the right of the c.g. The shovel contains a 20.0-N rock whose c.g. is 8.00 cm to the right of the edge of the shovel. How much force does the person exert down on the handle?