This is a very valid hypothesis for many reasons. One is that solar systems form from massive amounts of dust, ice, and debris that eventually form into planets and such. This means it is very possible for this 'excess material' if you will to have moved into orbit behind Neptune.
Answer:
3.72 kJ
Explanation:
QH = 6.45 kJ
TH = 520 K
Tc = 300 K
Qc = ?
By use of Carnot's theorem
Qc / QH = Tc / TH
Qc / 6.45 = 300 / 520
Qc = 3.72 kJ
A motion where gravity is the only force acting upon it
Endurance is the ability to complete extended periods of physical activity