8. What is the density of a rock with a volume of 5 cubic centimeters and a mass of 3 grams?

Can someone me with questions 12 and 13 plz.

In an investigation that uses the scientific method, which step immediately follows making a hypothesis? o summarizing the results o asking a question o making observations designing an experiment mark this and retum save and exit next submit

The twister and runaway train are two coasters at the same amusement park. both coasters start at the same height. the coaster for the twister is twice the mass of the coaster for the runaway train. which roller coaster has greater gravitational potential energy at the start of the ride?