Question

A particle with instantaneous velocity Vector V = (2i + 3j + xk)m/s and instantaneous acceleration vector a = 3i + 4.5 j - 6k m/s² . If path of the particle is a straight line then magnitude of x is :

Answer 1

vector a || v

(2i + 3j + xk) = 3i + 4.5j - 6k

x = 4.

Answer 2

As the motion of the particle is linear then the direction of instantaneous velocity and instantaneous acceleration vectors will have same direction. So the vectors are parallel

Hence x/-6=3/4.5=2/3

=> x= -4