Find the fake gold coin

There are 10 packs , each pack contain 10 units of gold coin.
As known that
1. One of the pack contain 10 units of fake gold coin, the rest of packs contain real gold coin.
2. The real gold coin wieght is 10g per unit, and the fake gold coin weight is only 11g.
Now, give you a weighting machine and request you to find out which pack is contain fake gold coin. However, you are only allow to use this weighting machine for 1 time.

The question is
How to use a weighting machine 1 time to find out the pack with fake gold coin.