Answer:
System D --> System C --> System A --> System B
Explanation:
The gravitational force between two masses m1, m2 separated by a distance r is given by:

where G is the gravitational constant. Let's apply this formula to each case now to calculate the relative force for each system:
System A has masses m and m separated by a distance r:

system B has masses m and 2m separated by a distance 2r:

system C has masses 2m and 3m separated by a distance 2r:

system D has masses 4m and 5m separated by a distance 3r:

Now, by looking at the 4 different forces, we can rank them from the greatest to the smallest force, and we find:
System D --> System C --> System A --> System B
Formula: s = d/t
s = speed
d = distance
t = time
Solve using the values we are given.
s = 300/40
s = 7.5m/s
Best of Luck!
Answer:
Winter
Explanation:
Earth Rotates about an axis
Because less energy is being wasted. non-renewable resources will last longer.
the cost is kept lower. hope it helps :)