Answer:
90°
Explanation:
First you must calculate the module or the magnitude of both vectors
The module of u is:

The module of v is:

Now we calculate the scalar product between both vectors

Finally we know that the scalar product of two vectors is equal to:

Where
is the angle between the vectors u and v. Now we solve the equation for


the answer is 90°
Whenever the scalar product of two vectors is equals to zero it means that the angle between them is 90 °