I believe the answer for 1) is
PEgrav = mass • g • height
PEgrav = m *• g • h
Metric system. important because it saves us time due to the fact that we do not have to convert our units every time.
'Newton-second' is dimensionally equivalent to 'kilogram-meter/second'.
] Ceres is composed of rock and ice and is estimated to comprise approximately one third of the mass of the entire asteroid belt. Ceres is the only object in the asteroid belt known to be rounded by its own gravity (though detailed analysis was required to exclude 4 Vesta). From Earth, the apparent magnitude of Ceres ranges from 6.7 to 9.3, peaking once every 15 to 16 months,[21]hence even at its brightest it is too dim to be seen with the naked eye except under extremely dark skies.
Answer:
Explanation:
The apparent brightness follows an inverse square law, therefore we can write:
where I is the apparent brightness and r is the distance from the Sun.
We can also rewrite the law as
(1)
where in this problem, we have:
apparent brightness at a distance 
, where
million km
We want to estimate the apparent brightness at 
, where is ten times , so
Re-arranging eq.(1), we find 
:
