G(where g=9.8 m/s2). if an object’s mass is m=10. kg, what is its weight?

An object's weight is

           (its mass) x (the acceleration of gravity wherever the object is) .

The acceleration of gravity on or near the Earth's surface is about 9.8m/s².

So an object with 10kg of mass, as long as it's located on or near the
Earth's surface, weighs
                                       (10 kg) x (9.8 m/s²) = 98 kg-m/s² = 98 Newtons.

                                                                      That's about 22.05 pounds.

If you take the object somewhere else, it's still 10 kg of mass, but
it weighs something different, depending on the gravity of the place
where you take it.

If there was no gravity then their would be no downword force on the football to have it return the the grownd, and if there was no friction (mainly air friction) then there would be no opposing force the stop the ball from moving through the air allowing the ball to travle ∞.