1. The ________ ________ of two vectors yields a scalar, rather than a vector.
2. The dot product of u = (u1, u2) and v = (v1, v2) is u ∙ v = ________.
3. If  is the angle between two nonzero vectors u and v, then cos θ = ________.
4. The vectors u and v are ________ if and only if u ∙ v = 0.
5. The projection of u onto v is given by projvu = ________.
6. The work W done by a constant force F as its point of application moves along the vector PQ is given by W = ________ or W = ________.