Answer:
The ratio of the orbital time periods of A and B is 
Solution:
As per the question:
The orbit of the two satellites is circular
Also,
Orbital speed of A is 2 times the orbital speed of B
(1)
Now, we know that the orbital speed of a satellite for circular orbits is given by:

where
R = Radius of the orbit
Now,
For satellite A:

Using eqn (1):
(2)
For satellite B:
(3)
Now, comparing eqn (2) and eqn (3):

Endless movement between hot and cold will eventually mean the end of the universe. This law is about inefficiency, degeneration and decay. <u>The second law can be expressed in several ways, the simplest being that heat will naturally flow from a hotter to a colder body. At its heart is a property of thermodynamic systems called entropy.</u> Entropy basically means an increase in randomness. Hope this helps mate.
D is correct, Gamma rays have the shortest wavelength.
Longitudinal waves transfer energy parallel to the direction of the wave motion
Answer:
In an elastic collision, the momentum is conserved and the mechanical energy is conserved too.
Explanation:
There are two types of collisions:
- Elastic collision: in an elastic collision, the total momentum before and after the collision is conserved; also, the total mechanical energy before and after the collision is conserved.
- Inelastic collision: in an inelastic collision, the total momentum before and after the colllision is conserved, while the total mechanical energy is not conserved (in fact, part of the energy is converted into other forms of energy such that thermal energy, due to the presence of frictional forces)