Answer:
(a) Ratio of mean density is 0.735
(b) Value of g on mars 0.920 
(c) Escape velocity on earth is 
Explanation:
We have given radius of mars
and radius of earth 
Mass of earth 
So mass of mars 
Volume of mars 
So density of mars 
Volume of earth 
So density of earth 
(A) So the ratio of mean density 
(B) Value of g on mars
g is given by 
(c) Escape velocity is given by

when wire is coiled upon a nail then it will posses magnetic characteristics
This is due to the coiled shape it will behave like a solenoid and the magnetic field of solenoid is given as

so here when wire is coiled up on a nail then due to the magnetic field of the coil the nail will attain magnetic characteristic.
so correct answer will be
<em>Possess magnetic properties </em>
Answer:
The oxidation number of a monatomic (composed of one atom) ion is the same as the charge of the ion. For example, the oxidation numbers of K+, Se2−, and Au3+ are +1, -2, and +3, respectively. The oxidation number of oxygen in most compounds is −2.
Explanation:
A force vector F1 points due
east and has a magnitude of 200 Newtons, A second force F2 is added to F1. The
resultant of the two vectors has a magnitude of 400 newtons and points along
the due east/west line. Find the magnitude and direction of F2. Note that there
are two answers.
<span>The given values are
F1 = 200 N</span>
F2 =?
Total = 400 N
Solution:
F1 + F2 = T
200 N + F2 = 400N
F2 = 400 - 200
F2 = 200
N