An iceberg is a body of ice floating in the ocean. A glacier is a land based 'river of ice' flowing from the mountains to its ultimate terminus, wherever that may be.
Thus they are very different things.
As to speed, like a river, that depends upon the gradient - in the cirques at the head, the velocity would be quite high, but slowing as the glacier grew and its gradient shallowed.
iceberg
Iceberg.
A glacier if it is on land; if it floats in the sea, it's called an iceberg.
iceberg
An Iceberg.
A glacier is older than an iceberg, because an iceberg is a piece of ice that fell off a glacier.
glacier
An iceberg
pressure is put on a glacier and causes a chunk of ice to float of on its own. This is a iceberg.
iceberg
An iceberg forms after a glacier flows into a body of water, like an ocean. When the top portion of the glacier breaks off and floats, this becomes the iceberg.
A large detached piece of a glacier is called an iceberg. The process by which this happens is called calving.There isn't really a term for a detached piece of an iceberg. See related question.
An iceberg
The end of the glacier where melting occurs.
Iceberg.
the iceberg that sunk Titanic may have been spawned from the Jakobshavn Glacier (western Greenland).
Calving is the process of the individual iceberg breaking off from the glacier snout, in the sea, or in a glacial lake. The iceberg is the calf.