Answer:
Part a)

Part b)
Here final kinetic energy is more than the initial kinetic energy
This increase in kinetic energy is due to spring connected between them as the spring energy is converted into kinetic energy of two blocks
Explanation:
Part a)
As we know that there is no external force on the system of two gliders
So here we can use momentum conservation for two gliders
So we will have




Part b)
now we will have
initial kinetic energy of both gliders is given as


Final kinetic energy of two gliders


so here final kinetic energy is more than the initial kinetic energy
This increase in kinetic energy is due to spring connected between them as the spring energy is converted into kinetic energy of two blocks
There are no appropriate units for power on the list you provided
The volume increases, but the surface area remains the same
<span>F = m*a = 7000kg * 9.8N/kg = 68,600 N.
68,600 N is your answer
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Explanation:
We have,
Surface area, 
The current varies wrt time t as :

(a) At t = 2 seconds, electrical charge is given by :

(b) Current is given by :

Instantaneous current at t = 1 s is,

(c) Current is, 
Current density is given by electric current per unit area.

Therefore, it is the required explanation.