   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.
Typical Schedule for 9 -12 Month Old. Babies at this age on average need 11 hours of sleep at night and 3 1/2 hours of sleep during the day. At nine months, babies should nap for about an hour and a half in the morning and about 1 1/2 to 2 hours in the afternoon. Most have given up that brief, third late-afternoon nap. By twelve months, the morning nap is about an hour, and the afternoon nap is about 1 1/2 hours.