No it is not legal to have any contact with the goalkeeper.
No, you can't.
A football with no air is heavier than a football with full air because the air adds buoyancy and makes it lighter.
Air resistance is a contact force because you are in contact with the air in order to apply that force.
A goalkeeper is considered to be in control of the ball when... ...the ball is between the hands or between the hand and any surface (e.g. ground, own body) ...holding the ball in the outstretched open hand ...bouncing it on the ground or throwing it in the air A goalkeeper cannot be challenged for the ball even when in the process of throwing or punting it.
air is in the football
Contact Air was created in 1974.
air!
The air inside the football expands in the heat, causing it to become harder. When the football cools down in the evening, the air inside contracts, making the football feel softer. Temperature changes can influence the pressure of the air inside the football, impacting its firmness.
to hold air
Air Force Falcons football was created in 1955.
Air India - football club - was created in 1952.
a softball. a football is filled with air, and air isn't very dense. obviously.