Birds on 'planes puzzle

Post Reply New Topic

Ok then, so-called geniuses, answer me this.

An aeroplane carries, in its hold a large number of birds.

These birds are not in transit packaging and are free to fly around the hold at will.

The aeroplane takes off, with the birds sitting quietly on perches provided for them.

Halfway through the flight, a flight attendant enters the hold and lets off a firework, causing all the birds to take flight at once.

How does the fact that the birds are in flight affect the mass of the aeroplane?

Unless the firework punched a hole through the hull of the airplane, its mass is unaffected.

The simultaneous takeoff of the large number of birds will produce a equal and opposite reaction on the airplane - but since its mass is so much larger than all the birds put together the force will have only a microscopic effect on the plane's lift.

Interesting. I was about to say it'd lessen the weight of the airplane, but that's not what this riddle is asking, right?

The mass of the aeroplane would remain the same.

As for the mass of the aeroplane and its contents ... well now, that's a different question altogether.