What is the projectile motion equation?
Basically, any of the kinematic equations works, if you know when to use which equation.
For a projectile shot at an angle, to find time, first consider the first half of the motion. You can set up a table to organize what you have and what you need to figure out which kinematic equation to use.
For example: A child kicks a ball with initial velocity of
You can start with the table of givens. For time you're going to need the y-component of the velocity.
You can use the kinematic equation
REMEMBER that this is only for the first half of the motion, so multiply the calculated time by
So, the moral is, if you can identify what the question is asking for, and you can find the givens, organize them into a table similar to the one I made, and chose the appropriate kinematic equation, you should be fine. Sorry if this was a bit long.