if an empty box van weighs 4000 lbs and 1000 pidgeons are then placed inside each weighing 1 lb, the total when the birds are seated is 5000 lbs. how much does the box van weigh when the birds are not seated but airborne within the box van. does the box van weigh the original 4000 lbs because the birds are flying? or does the weight remain the same as if the birds are seated? or is the total weight greater because the gravitational downward force of the birds wings is greater than the weight of the birds at rest?
2006-08-12 10:41:05 · 10 answers · asked by austin d 1 in Science & Mathematics ➔ Mathematics
The weight stays the same.
When the birds fly inside the van, they exert a net force equal to their weight through the air, which is reacted against by the walls and floor of the van.
If they all took off together, the weight might momentarily increase, as the birds accelerate to reach an elevated position.
2006-08-12 10:47:22 · answer #1 · answered by Anonymous · 3⤊ 0⤋
Higher than 5000 lbs when they are lifting off and 5000 lbs when they are maintaining the flight.
The birds have to exert a DOWNWARD THRUST to lift off and stay flying. This would be more than their weight at lift off as they are accelerating upwards, and it would be1000 lbs when they are already up.
2006-08-13 09:39:43 · answer #2 · answered by Kemmy 6 · 0⤊ 0⤋
it shall be 5000 lbs but to be precise it may even cross 5000 when the birds accelerate upwards.
the concept to be kept in mind is Newtons 3rd law.
how do birds rise? they exert force equal(also greater to accelerate) to their body weight downwards on the surrounding air in reacton the air provides them force >= their weight and so they elevate.
this concept also is used in helicopters choppers etc.
i hope u got my point
2006-08-13 01:03:40 · answer #3 · answered by Prince Stan 3 · 0⤊ 0⤋
4000 Ibs. Only if the birds are touching the van would the weight increase. If they are airbourne, they do not affect it.
2006-08-12 19:47:14 · answer #4 · answered by Cagalli 1 · 0⤊ 1⤋
4000 lbs
2006-08-12 18:08:12 · answer #5 · answered by Hasan 2 · 0⤊ 1⤋
4000 lbs
The birds are not exerting any force on the van since they are not perched.
2006-08-12 17:58:22 · answer #6 · answered by falexge 2 · 0⤊ 1⤋
I agree it stays the same otherwise there would be matter created out of nothing
2006-08-12 17:50:03 · answer #7 · answered by Fram464 3 · 0⤊ 0⤋
It is more than 4000lb but less than 5000lb
2006-08-13 05:43:09 · answer #8 · answered by Clinkit 2 · 0⤊ 1⤋
same as before
2006-08-13 01:38:43 · answer #9 · answered by Anonymous · 0⤊ 1⤋
4000lbs
2006-08-12 17:49:37 · answer #10 · answered by R S 2 · 0⤊ 1⤋