Two are true, one is not

Exercise and reference answers

Questions

1. False statement

   a · b returns a vector

   Statements

   1. a · b uses cos θ
   2. a × b uses sin θ
   3. a · b returns a vector

2. False statement

   Every vector of magnitude 1 is the zero vector

   Statements

   1. Every vector of magnitude 1 is the zero vector
   2. A unit vector has magnitude 1
   3. The zero vector has no definite direction

3. False statement

   Direction ratios are always unit length

   Statements

   1. Scalar components of a vector are its direction ratios
   2. Direction ratios are always unit length
   3. l = a/r, m = b/r, n = c/r relate cosines to ratios

Explanation