1. An object initially at rest falls from a height H until it reaches the ground. Two of the following energy bar
charts represent the kinetic energy K and gravitational potential energy Us of the object-Earth system at
two positions. The first position is when the object is initially released, and the second position is when the
object is halfway between its release point and the ground. Which two charts could represent the mechanical
energy of the object-Earth system? Select two answers.

Aflask with vinegar in it has a mass of 160 grams. a balloon with baking soda in it has a mass of 40 grams. the balloon is attached to the flask to seal the opening and the vinegar and baking soda mixes. the balloon inflates to a large volume. what will the total mass of the balloon and flask be after the balloon inflates? explain. a) less than 200 grams because the solid baking soda disappears. b) 200 grams, because all the atoms remain in the balloon or flask. c) more than 200 grams because the size of the balloon is so much larger. d) less than 200 grams because gases such as the one in the balloon are lighter than solids and liquids.