The most modern form of magnetisation is to take a ferrous metal, like iron, and subject it to either an opposingly-charged electrical or magnetic field.
shrapnel is a piece of metal. for example when a bomb explodes it creates shrapnel
A sharp metal piece is typically called a "metal shard" or a "metal splinter."
A 'metal filing ' is a tiny piece of metal that is rubbed off from a large piece by a file.
You can't. You might be able to demagnetize it, but then it's no longer a magnet, it's just a piece of metal.
due to heat generated by friction of two metallic surfaces
A metal burr is a small, thin edge of metal that is created when a piece of metal is machined. For example: when a chef's knife is sharpened, a thin piece of metal remains on the edge of the knife.
its a piece of curved metal with another piece of metal going through it at the top
You might be able to go to a machinist and have them bend and weld a cone shaped piece of sheet metal for you.
If the piece of sheet metal is a square, then 1600 cm2.
This might be a description of a radio antenna.
Metal can become a temporary magnet when it is placed near a strong external magnetic field, aligning its domains in the same direction as the field. Once the external field is removed, the alignment of the domains gradually returns to their original random state, causing the metal to lose its magnetism.
Of itself a metal can not be "shortened". However, a metal OBJECT such as a piece of metal wire can be shortened by cutting a piece off. This would be a physical change.