Question

The motion of a particle on a straight line is given by s=t^3-6t^2+12t-8. When does the object change its direction?

Answer 1

Set v=0 to find when the particle is stationary
For that given time (t=..), find the x value.

Answer 2

t=2 is that when it changes direction?

Answer 3

yes

Answer 4

But the answer booklet says 2 is not the answer

Answer 5

For that given time (t=..), find the x value.

Answer 6

sub t=2 into x or s=....

Answer 7

for s that given time is 0

Answer 8

what does that represent?

Answer 9

what?

Answer 10

like when i plug in t=2 for the position function i get 0 is that the answer?

Answer 11

is that what the answers say?

Answer 12

Uh well the answer choices are A)1 B) 2 C) 3 D) 0 E) None of these. And the correct answer was e.

Answer 13

I dont know then, the method is definitely correct though.

Answer 14

Oh alright then maybe there is a mistake on the answer but thank you anyway (:

Answer 15

My bad
If you look at the velocity graph, the velocity is always positive

Therefore it never changes direction