You are right, it's not hard to derive them at all. You just need to be able to integrate properly. Most the time, you get simple things to integrate.
Then comes mechanics, which is like projectile motion in harder terms, and tougher conditions/considerations. Here, you might get some nasty things to integrate, nasty meaning long and tedious things involving logs and stuff...
Projection motion (Physics) is to Projectile motion (3U) as Projectile motion (3U) is to Mechanics (4U) as Parabola (3U) is to Conics (4U).