If vector `hati- 3hatj+5hatk and hati-3hatj-ahatk` are equal vector then find the volue of a.

Options

A. `a=5`
B. `a=-15`
C. `a=15`
D. `a=-5`

Answer

D

Explanation

Two vectors are said to be equal if their magnitude is equal i.e.,A=B
Here `A=hati-3hatj+5hatkand B=hati-3hatj -ahatk`
` implies hati-3hatj+5hatk=hati-3hatj-ahatk`
Comparing on both sides , we get
a=-5