Either they have less density than air,
or they have some device (like wings) that supplies lift.
Gravity.
Objects that float in air are typically those that are less dense than the air around them, such as helium balloons or lightweight objects like feathers. These objects are able to displace enough air to generate an upward force greater than the force of gravity acting on them, allowing them to float.
yes. that is why you are able to see objects. light reflects off objects allowing you to see.
no NO PLANE CAN STAY IN AIR EXPECT HELICOPTER JUST BECAUSE OF HIS WINGS
w does a seaplane fly and be able to stay iin the air
Things float in the air when the force of buoyancy (upward force exerted by air or a fluid) is greater than the force of gravity (downward force pulling objects toward the earth). This is known as buoyancy and is what allows objects to float or stay suspended in a fluid or gas like air.
If objects didn't have mass, they wouldn't have any inertia or gravitational attraction. This would mean that they would not be able to interact with each other or respond to forces. Essentially, the entire concept of matter and physics as we know it would be completely different.
Light because the wind is able to carry the disc farther.
No, air alone cannot support solid objects in sustained flight. In order for an object to achieve sustained flight, it needs additional propulsion or lift mechanisms such as wings, rotors, or jets to counteract gravity and stay airborne.
Gravity is the force which keeps them there.
All objects want to stay where they are. This is a simple rule of physics. It is called Inertia. When an object passes through the molecules that are in the air, the air particles, which want to stay where they are try to force the object that is moving, or indeed as you mentioned; falling to stay in its position. Because air can not do this, you get the effect which is called terminal velocity - the speed at which an item can travel at it's maximum through our atmosphere. The effect of air means that falling objects can only hold up the constant acceleration due to gravity for a certain period of time before the object stops accelerating. Another interesting effect that objects falling at high speed heat. This is due to the object that is moving smashing into the air molecules. This transfers energy and causes heat.
Objects that increase air resistance include large surface area objects (such as flags or parachutes), rough or uneven surfaces, and objects with irregular shapes (such as a car spoiler or a parachute harness). These objects create more friction with the air as they move, resulting in higher air resistance.