Why does our pubic hair (or body hair) grow back a lot faster then your own hair on your head?

Now I can’t be the only one that’s curious about this!
I’ve always noticed when I did shave my leg or arm or armpit or etc (a lot in the past but not a lot now) that my pubic hair or body really would just grow. An I mean grow back faster and longer. But then that got me thinking, if someone were to cut there hair on there head that was really long and made it short. Then want to grow it back, how come it doesn’t grow back as fast as your pubic hair, but takes years to grow? The hair on your head is apart of your body so why not?