Amass of 0.074 kg hangs from a vertical spring in the lab room. you pull down on the mass and throw it vertically downward. the speed of the mass just after leaving your hand is 3.40 m/s. (a) while the mass moves downward a distance of 0.09 m, how much work was done on the mass by the earth? include the appropriate sign. work done by earth = j (b) at the instant in part (a) when the mass has moved downward a distance of 0.09 m, the speed of the mass has decreased to 1.39 m/s. how much work was done on the mass by the spring? include the appropriate sign. work done by spring = j