Find total displacement of the particle in motion

[iman.f]

hello everybody,
what is the total displacement of the particle at first 4 second?

equation (x) versus (t) : X = 3T^2 - T^3 where x is in meter and t in second.

my solution is : v= 6t-3t^2 , 6t-3t^2=0 , t=2 ,

X(2)= +4 , X(4)= -16 ,: displacement of the particle at first 4 second is: -16 m

BUT I'm not sure which my answer is right. please guide me.

 

[HallsofIvy]

Yes, in the first 4 seconds, the particle moved from 0 to -16 and so the displacement is -16 m.

But the wording of the problem bothers me. What is total displacement?

Since the particle moved 4 meters to the right, then -20 meters to the left, the total distance (not displacement) the particle moved is 24 meters.