You have written the answer within your question.
mass of 1kg metal is "1 kilogram"
but when you talk about it's weight
then,
it's weight is 9.8 Newton.
Answer:
The only liquid elements at standard temperature and pressure are bromine (Br) and mercury (Hg).
Here, you can derive that by numerical method, as follows:
F = m.a
m = F/a
So, here we can see when we decrease one, other increase by same effect; we can say they are "Indirectly Proportional" to each other!
Hope this helps!
It lets the viewer know it's something to do with underwater.