Discuss the examples in the video that explained the transfer of kinetic energy to thermal energy?

Watch this video: https://www.youtube.com/watch?v=9qHrzs6Mbp4
Tides and energy transfer
4.1 What is the equation for differential gravity and explain that equation.
4.2 Considering an elliptical orbit, when is the tidal force stronger, when the satellite is closer or father away from the star or planet?
4.3 Discuss the examples in the video that explained the transfer of kinetic energy to thermal energy? Which demo is most like what happens in tidal heating?
4.4 What is orbital resonance?