The average (non-bald) person has 100,000 hairs on their head. Hair grows at a rate of 1/2 inch per month.
That means you grow 50,000 inches of hair per month.
That is 1667 inches per day.
That is 138 feet *per day*!!!
Or about 1/50th of an inch a second!
That is a lot of work! I wonder what percent of our nutritional intake is used for this?
1 foot of a head of hair weighs about 50g. So one foot of a single hair weighs 50g/10e5 == 0.0005 g.
At 6 feet / hour, that is 0.003g / hour (minimum) going into hair production. Hmm, that's not very much.