$A$ charged object is launched inside a time-varying electric field. Its motion is recorded by a video camera on a video tape. When it is at a certain moment $A$,its position vector $\vec{r}$,velocity $\vec{v}$,and acceleration $\vec{a}$ are measured. $A$ student watches the video at a later time but mistakenly plays the tape in the reverse direction. What are the position,velocity,and acceleration of the object at moment $A$ observed by the student,respectively?

  • A
    $\vec{r}, \vec{v}, \vec{a}$
  • B
    $-\vec{r}, -\vec{v}, -\vec{a}$
  • C
    $\vec{r}, -\vec{v}, \vec{a}$
  • D
    $\vec{r}, \vec{v}, -\vec{a}$

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