You calculated the density correctly.
When you drop anything into a fluid . . .
-- If the object is MORE dense than the fluid, it sinks.
-- If the object is LESS dense than the fluid, it floats.
The electrostatic force between two charges is given by

where
ke is the Coulomb's constant
q1 and q2 are the two charges
r is the separation between the charges
In our problem,



Therefore the electrostatic force is
Answer:

Explanation:
Given that,
The magnitude of vector A, 
The magnitude of vector B, 
Scalar product of A and B, 
The formula for the scalar product is given by :

Where,
is the angle between A and B.

The formula for the vector product is given by :

So, the vector product between these two vectors is
.
Answer:
We can determine the age of the Earth and the rocks found on Earth with techniques such as measuring ice cores and digging and analysing fossils.
Explanation:
Hopefully this helped!
Answer: electronegativity
Explanation:
Electronegativity is defined as the property of an element to attract a shared pair of electron towards itself.
The size of an atom decreases as we move across the period because the electrons get added to the same shell and the nuclear charge keeps on increasing. Thus the electrons get more tightly held by the nucleus.
As, the size of an element decreases, the valence electrons come near to the nucleus. So, the attraction between the nucleus and the shared pair of electrons increases and thus the electronegativity increases.