Question

1.4.2 test (cst): computer - scored unit test
how does the comets energy change as it moves from point a to point d?
a. ke increases, gpe decreases
b. ke decreases, gpe increases
c. ke increases, gpe increases
d. ke decreases, gpe decreases

Explanation:

Step1: Recall energy - distance relationship

As a comet moves away from the sun (from point A to point D), the gravitational potential energy (GPE) increases because gravitational potential energy is given by $U =-\frac{GMm}{r}$ and as $r$ (distance from the sun) increases, the magnitude of the negative - valued GPE becomes smaller (i.e., it increases in value).

Step2: Recall conservation of mechanical energy

The total mechanical energy (sum of kinetic energy KE and GPE) of the comet - sun system is conserved in the absence of non - conservative forces. So, as GPE increases, kinetic energy (KE) must decrease to keep the total energy constant.

Answer:

B. KE decreases, GPE increases