   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.
Understand Your 2-Year-Oldâs Sleep Needs. As your child grows, the amount of sleep they need changes, both for nighttime and naps. Your 2 year old needs an average of 12 hours of sleep, with 10 Â½ -11 hours being at night, and between a 1 Â½ to 2 hour long afternoon nap. I have spoken to families on all ends of the sleep spectrum, and Iâve found that many are surprised by this number.