Vector Multiplication: Dot & Cross Products

[AlchemistK]

I have read of dot product and cross product to multiply vectors, yet i do not understand the theory behind them. What are vector products even used for?


Thank you.

 

[Fewmet]

I have read of dot product and cross product to multiply vectors, yet i do not understand the theory behind them. What are vector products even used for?


Thank you.

I watched the first five minutes of this http://www.youtube.com/watch?v=E34CftP455k". It looks like a decent place to start and is not dense in terminology.

Many equations in physics and elsewhere call for multiply two vectors by each other. That's where I see them used.

 

[Vagn]

I have read of dot product and cross product to multiply vectors, yet i do not understand the theory behind them. What are vector products even used for?


Thank you.

One use of the vector product is in Electromagnetics. For example the force on a charged particle moving in a magnetic field is:
F_B=qvXB
Where F_B is the force q is the charge, v is the particle's velocity and B is the magnetic field strength.

 

[SteamKing]

Cross product of a radius vector and a Force vector yields a moment or torque vector.
Dot product between identical vectors gives the square of the magnitude of the original vector.
Dot product between two arbitrary vectors yields the projection of one vector on the other.

 

[AtomicJoe]

I have read of dot product and cross product to multiply vectors, yet i do not understand the theory behind them. What are vector products even used for?


Thank you.

Seems to me the key thing is the resultant vector for cross product is not in the same plane.
So if you have two vectors in the x and y planes, the the resultant in in the z plane.

However I am no expert, I'm just guessing it comes from something like electro magnetic forces
where the motion of a charged particle is in one plane, the field in another and the current in another.