Question

The projection of a vector `vec(r )=3hat(i)+hat(j)+2hat(k)` on the `x-y` plane has magnitude
A. 2
B. `sqrt(14)`
C. `sqrt(10)`
D. `sqrt(5)`

Answer 1

Correct Answer - C
`vec(R )= 3hat(i)+hat(j)+2hat(k)`
`:.` Length in XY plane `= sqrt(R_(x)^(2)+R_(y)^(2))= sqrt(3^(2)+1^(2))= sqrt(10)`