In: Physics
5. With each stated property, give an example of the 2-space
vector field F(x,y). (a) F has a constant direction, but ||F||
increases when moving away from the origin. (b) F is perpendicular
to the vector field and ||F||=5 everywhere.
F(x,y) is a 2 space vector
a) F is constant in direction but ||F|| increases when moving away from origin
Think of F as
-------(1)
where x is variable and a is constant
We can consider a as zero also , hence F has constant direction i.e. +ve x axis direction even for non zero a
As a is constant ||F|| increases as x increases
Field F(X,Y) of (1) satisfies both conditions of constant direction and increasing NORM as we move away from origin
b) For ||F|| to be 5 everywhere there are many possibilities of coefficients of x and y
But for F to be perpendicular let us take
such that
Hence
Now for F to be perpendicular to vector field
We can think x=0
then
This is required result