How can I make an arrow go faster?

I'm trying to make a custom enchant that increases the speed of a projectile but I don't know what I would have to do to do that.

 

Multiply it's motion?

Code:

arrow->setMotion(arrow->getMotion()->multiply(4))

 

I'll try that, thanks.

 

Look what I found: docs.pocketmine.net/EntityShootBowEvent.php and this is how currently force is calculated

PHP:

# pocketmine/item/Bow.php (Line: 62 - 64)
/* 62 */ $diff = $player->getItemUseDuration();
/* 63 */ $p = $diff / 20;
/* 64 */ $force = min((($p ** 2) + $p * 2) / 3, 1) * 2;


I'm sure that $event->setForce($event->getForce() * 2) will do fine

 

That's much cleaner, but will it multiply the damage too?