Because the Moon has a very small surface area compared to other spacial geo-bodies, it has cooled down much faster than Earth. Any water on the moon would freeze.
Answer:
A. 1.64 J
Explanation:
First of all, we need to find how many moles correspond to 1.4 mg of mercury. We have:

where
n is the number of moles
m = 1.4 mg = 0.0014 g is the mass of mercury
Mm = 200.6 g/mol is the molar mass of mercury
Substituting, we find

Now we have to find the number of atoms contained in this sample of mercury, which is given by:

where
n is the number of moles
is the Avogadro number
Substituting,
atoms
The energy emitted by each atom (the energy of one photon) is

where
h is the Planck constant
c is the speed of light
is the wavelength
Substituting,

And so, the total energy emitted by the sample is

Answer:
a) 4.2m/s
b) 5.0m/s
Explanation:
This problem is solved using the principle of conservation of linear momentum which states that in a closed system of colliding bodies, the sum of the total momenta before collision is equal to the sum of the total momenta after collision.
The problem is also an illustration of elastic collision where there is no loss in kinetic energy.
Equation (1) is a mathematical representation of the the principle of conservation of linear momentum for two colliding bodies of masses
and
whose respective velocities before collision are
and
;

where
and
are their respective velocities after collision.
Given;

Note that
=0 because the second mass
was at rest before the collision.
Also, since the two masses are equal, we can say that
so that equation (1) is reduced as follows;

m cancels out of both sides of equation (2), and we obtain the following;

a) When
, we obtain the following by equation(3)

b) As
stops moving
, therefore,

Answer:
The mass of the gold bar is 1,544 g
Explanation: