A particle `P` is moving with a constant speed of `6 m//s` in a direction `2 hati-hatj+2hatk`. When `t=0, P` is at a point whose position vectors is `3hati+4hatj-7hatk`. Find the position vector of the particle `P` after `4` seconds.

Options

A. `18hati-4hatj-23 hatk`
B. `19hati-4hatj-23 hatk`
C. `19 hati+4hatj-23hatk`
D. `19hati-4hatj+23 hatk`

Answer

B

Explanation

`vec(V)=6(2 hat(i)-hat(j)-2 hat(k))/(3)`
`vec(r)=vec(r)_(0)+vec(v)t=3 hat(i)+4 hat(j)-7 hat(k)+4 xx2`
`(2 hat(i)-hat(j)-2 hat(k))rArr vec(r)=19 hat(i)-4 hat(j)=23 hat(k)`.