Answer:
g₂ = 11 m/s²
Explanation:
The value of free-fall acceleration on the surface of a planet is given by the following formula:

where,
g = free-fall acceleration
G = Universal Gravitational Constant
m = mass of the planet
r = radius of planet
FOR PLANET 1:
--------------------- equation (1)
FOR PLANET 2:

using equation (1):

<u>g₂ = 11 m/s²</u>
D; solar system, because the planets are inside it.
Using the equation for period length, you get an answer of about 4.1 seconds.
I'm pretty sure the energy an object acquires when exposed to a force is known was potential energy.