The pair of elements with the most similar chemical properties are a. Na and F
b. O and Kr
c. Ne and Ar
d. Mg and Cl

Two objects of different mass start from rest, are pulled by the same magnitude net force, and are moved through the same distance. the work done on object 1 is 900 j. after the force has pulled each object, object 1 moves twice as fast as object 2. how much work is done on object 2?