   A heavier plane has more momentum (when thrown at the same speed),  but it's also got more downward force acting on it. If it has the  same wing area, though, it has the same lift, so it drops more  quickly than a light plane (objects fall at the same speed only in  the absence of air resistance).
By 2 months, baby's bedtime should be between 6:00-8:00pm and should occur about 1 hour after the last nap ends. 3 months: babies this age should be on a solid 4 nap schedule with the last nap of the day ending by 5:00pm.
The sooner you establish a bedtime routine, the better. When your baby is as young as 6 or 8 weeks old, start following a set pattern every night. She'll quickly come to appreciate the consistency and predictability. A bedtime ritual is often good for parents, too. It's a special time set aside for you to spend with your baby, something you can plan on.