The mass of a football player who weighs 1250N

Ah hah! That depends on where he weighs 1250N, because

weight depends not only on mass but also on the local gravity.

So the same mass can have different weights in different places,

and the same weight can indicate different mass in different places.

Weight = (mass) x (acceleration of gravity).

Note: 1250N is almost exactly 281 pounds.

- - If he weighs 1250N on Mars, then his mass is 336.8 kg.

- - If he weighs 1250N on Earth, then his mass is 127.5 kg.

- - If he weighs 1250N on the Moon, then his mass is 770.2 kg.