15 hp level - 60 hp steeo grade

https://share.google/aimode/ufyyJUoxxPKcVgK6Q

a car might require 15 hp to travel on level ground

but on a 8% grade the car will require 60 hp

so 15 horse can pull you on level ground but 60 horses are needed to
pull you up a steep grade

and - yes - 1 HP means exactly what it sounds like - sorta -
https://share.google/aimode/ukVMwPfp3AlqIvzR9

humans can produce 2.5 hp on a good day - horses can crank up to 15 hp
- but 1 HP is their typical output averaged over an entire day

a human can usually do 1 HP - so lets see if we can remember that - 1
HP actually equals 1 humanPower