this is not scientifically correct but you can think of horsepower like this

when ur going really fast you need to put alot of force onto the pavement to accelerate or keep it at a constant speed because of air resistance, at 6000 rpm you may have low torque (but high horsepower) but since you're putting a little bit of torque each stroke, 6000 of those a minute is quite alot of force agaisnt the road, so you can think of it like net force

in 1 minute how much torque can u put down (hp is a function of work and time and work is force and displacement but for arguments sake remove that from the equation) thats what horsepower is about

but when coming out of a corner you need torque (unless u shift down) because ur engine is at such low revs you want to put down as much force onto the road per stroke since ur doing so little revs ... i hope this makes sense to the people who either havnt taken physics or dont understand it

its extremely simplified and if u told even a grade 9 physics teacher this he'd fail u but its just to make this easy to understand