If gravity pulls objects toward the earth's surface, how can birds/airplanes fly?

Answer 1

When the force of gravity is balanced by another force, the object will fly. In the case of birds and airplanes, that other force is lift. Lift is generated by the wings, which push air downward as they move horizontally forward. The downward movement of the air generates an equal and opposite reaction according to Newton's third law. That opposite reaction is the lifting force that keeps the bird or plane in the air.

Answer 2

Good question. Here's how it works. An airblane (or bird) wing is curved on top and flat on the bottom. When the wing moves through the air, this means the air has more disance to travel over the wing. There's a physical principle (Carnot's Law) that tells us what happens in such situations: the air will move faster--but the pressure will drop.

The result is that the pressure on the bottom of the wing is higher thn on the top--producing lift. If the pressure difference iis fairly high--sayabout 5%-thats about 50 lbs of force on every square foot of the planes wings--pushing directly upward. That's a lot of force--and that's what lifts a plane off the ground and enables it to fly.

Of course you need to have a good engine (or strong wings if you''re a bird) to produce enough thrust get moving fast enough to make the air flow and lift strong enough--especially since they also have to overcome air resistance (called drag) as well. That's why aircraft need long runways--so they can get up enough speed.

To sum this up--the physical law that describes how airplanes and birds fly is: When thrust plus lift exceed weight plus drag, the plane (bird) will fly.

Answer 3

Birds have super-powerful wings that allow them to stay in the air along with feathers that allow air resistance to help them stay in the air.

Airplanes are round on the top of their wings, but flat on the bottom. At extremely fast speeds, the air resistance on the top of their wings is less than that on the bottom, pushing the airplane into the sky.

Answer 4

If that query replaced into on a try, i ought to call it a trick question. Gravity is measured in gadgets of stress(pounds in accordance to density, G-stress), no longer velocity. on earth's floor an merchandise is pulled to the earth at a stress of one G-stress. The added away an merchandise receives from the earth into area, the a lot less gravitational stress that merchandise thoughts. to attempt to respond to your question, the speed in accordance to 2d relies upon on quite a few variables. outdoors of the earth's environment that fee relies upon immediately on the gap of the article from the earth. it will be graphed as a curve with speeds increasing the closer it receives to the earth. If that merchandise meets no resistance, it really is going to proceed increasing in velocity until eventually it impacts the earth's environment. contained in the ambience, it really is a thoroughly diverse problem. An merchandise being pulled to the earth by technique of gravity is likewise experiencing the stress of resistance from the ambience. An merchandise will consistently have a tendency to velocity or sluggish to a velocity at which the stress of gravity and the stress of resistance are equivalent. That velocity is termed terminal velocity. What that velocity truly is relies upon on quite a few extra variables. An merchandise with a mess of floor section compared to its mass (like a fluffy feather) will adventure a mess of resistance compared to gravitational stress and would have an truly sluggish terminal velocity of a few thing like a million or 2 ft in accordance to 2d. An merchandise with a small floor section compared to it really is mass (like a bowling ball) would have a a lot swifter terminal velocity of a few thing like three hundred ft in accordance to 2d or a touch over 2 hundred miles in accordance to hour. At a lot larger elevations the ambience is way less dense and elements a lot less resistance. an identical gadgets ought to have a larger terminal velocity at larger altitudes.

Answer 5

Because it is not an absolute force. If gravity didnt hold us to the earth, birds, planes, dogs..all of us would jsut float off into space...especially considering how fast the earth is rotating.

Answer 6

They push against the air to counter the force of gravity.

Answer 7

Well if they both stop flying in mid air I guess you would find out now would'nt you. Boy what a waist of five points

Answer 8

The shape of the wing (aerofoil) in stream of air provides lift

Answer 9

if birds stopped flapping their wings , they would fall to Earth. if planes turned their jet engines off during flight , they would fall to Earth. no mystery here.

Answer 10

they pass the air with their wings and they can flying in the sky