$A$ box of mass $m$ is released from rest at position $1$ on the frictionless curved track shown. It slides a distance $d$ along the track in time $t$ to reach position $2$, dropping a vertical distance $h$. Let $v$ and $a$ be the instantaneous speed and instantaneous acceleration, respectively, of the box at position $2$. Which of the following equations is valid for this situation?

37-730

  • A

    $h = vt$

  • B

    $h = (1/2)gt^2$

  • C

    $d = (1/2)at^2$

  • D

    $mgh = (1/2)mv^2$

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