In the figure, a spring of spring constant 3.00 x 10
4 N/m is between a rigid beam and the output piston of a hydraulic lever. An empty container with negligible mass sits on the input piston. The input piston has area
Ai, and the output piston has area 14.0
Ai. Initially the spring is at its rest length. How many kilograms of sand must be (slowly) poured into the container to compress the spring by 2.30 cm?