Tha atmosphere has no effect on gravity.
Keplers laws states that planets sweep areas in equal times is second
I think it should be option (b)
Answer:
9 joules of heat energy was produced
Explanation: there is no acceleration therefore its not a kinetic energy
Energy= force × distance
= 3×3
=9
Answer:
Part a)

Part b)

Explanation:
As per momentum conservation we know that there is no external force on this system so initial and final momentum must be same
So we will have




Part b)
By equation of kinetic energy we have



