bootstrapping and the need for a capacitor

hi! i'm a new member of this site and i would like to ask you some questions. what is the concept of bootstapping?

and i saw a schematic of a fan having a capacitor in parallel with it, what is that for? i oftenly see fans with diode across it but not capacitor...

THANK YOU AND GOD BLESS!!!

If you don't know a motor needs a bit more power on start.

The capacitator suplys the lithe spike of power to get the motor strarted.