   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.
At 3, most children are still napping, while at 5, most are not. Naps gradually become shorter as well. New sleep problems do not usually develop after 3 years of age. 7-12 Years Old: 10 - 11 hours per day.At these ages, with social, school, and family activities, bedtimes gradually become later and later, with most 12-years-olds going to bed at about 9 p.m.There is still a wide range of bedtimes, from 7:30 to 10 p.m., as well as total sleep times, from 9 to 12 hours, although the average is only about 9 hours.12-18 Years Old: 8 - 9 hours per day.t 3, most children are still napping, while at 5, most are not. Naps gradually become shorter as well. New sleep problems do not usually develop after 3 years of age. 7-12 Years Old: 10 - 11 hours per day.