Answer:
A) 15.0 years
Explanation:
Due to the distance to the star system is in light-year units, we can compute the time by using:

then, Rob will take to complete the trip about 15 light-years.
hope this helps!!
Answer:
b. active solar heating systems
Explanation:
A solar collector is a device that collects and/or concentrates solar radiation from the Sun. These devices are primarily used for active solar heating and allow for the heating of water for personal use.
Answer:
The mass of the planet is 
Explanation:
Given that,
Time period = 42 hours = 151200 sec
Orbital radius = 0.002819 AU = 421716397.5 m
Mass of moon 
We need to calculate the mass of the planet
Using Kepler’s third law


Where, a = orbital radius
T = time period
G = gravitational constant
M = mass of moon
m = mass of planet
Put the value into the formula





Hence, The mass of the planet is 