A particle $P$ moves on the number line shown in figure A. The position of $P$ as a function of time $t$ is shown in figure B. (Note: The graph of $y = f(t)$ shown in figure B is not the path of the particle; it is a plot of the particle's position versus time.) (a) When is $P$ moving up?  help (intervals or inequalities) (b) When is $P$ standing still?  help (intervals or inequalities) (c) When is the velocity of $P$ negative?  help (intervals or inequalities) (d) On a sheet of paper, graph the particle's velocity and speed (where defined).

A   B

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