12. Which of the following observations provides the best evidence for the claim that gravity acts between objects across a distance?
A. Heavier objects have more gravity acting on them
B. The moon orbits Earth due to a gravitational field
C. An object at rest on the ground doesn't respond to gravity
D. Objects float freely in space where there is no gravity

answer: the potential energy decreases from 379 j to 243 j

explanation:

for the law of conservation of energy, the total energy in a system must be conserved. the total energy of the system is given by the sum of kinetic (k) and potential (u) energy:

e = k + u

the total energy is e=675 j, and this does not change.

initially, the kinetic energy is k=296 j, so the potential energy is

at the end, the kinetic energy is k=432 j, so the potential energy is

so, we see that the potential energy has decreased from 379 j to 243 j.