posted by james .
how do i solve this, i tried dividing the mass by the height, but its wrong
A 407-kg pile driver is raised 15 m above ground.
(a) How much work must be done to raise the pile driver?__kj
(b) How much work does gravity do on the driver as it is raised?__kj
(c) The driver is now dropped. How much work does gravity do on the driver as it falls?__ kJ