In: Physics
A)
Let the vector be given as
= a 
 + b
 + c

Magnitude of vector is given as
|
|
= sqrt(a2 + b2 + c2)
Multiplying vector by "2" both side
2
= 2a 
 + 2b
 + 2c

magnitude of the new vector is given as
|2
|
= sqrt((2a)2 + (2b)2 + (2c)2)
|2
|
= 2 sqrt(a2 + b2 + c2)
|2
|
= 2 |
|
hence we multiply by a factor of "2"
B)
multiplying a vector by a scalar factor of "2" only changes the magnitude and the direction of the vector remains the same.
So multiplicative factor in case of direction angle is "1"