A caterpillar is climbing vertically on a leaf. Its motion is shown on the following graph of vertical position yy y y vs. time tt t t . 1\small{1} 1 2\small{2} 2 3\small{3} 3 4\small{4} 4 5\small{5} 5 6\small{6} 6 7\small{7} 7 8\small{8} 8 9\small{9} 9 1\small{1} 1 2\small{2} 2 3\small{3} 3 4\small{4} 4 5\small{5} 5 6\small{6} 6 7\small{7} 7 y(m)y(\text m) y(m) t(s)t(\text s) t(s) Graph of y (in meters) vs. t (in seconds) that starts at 6 m at 0sec, decreases linearly to 2m at 4 sec, stays constant at 2m from 4 sec to 7 sec, increases linearly to 5 m from 7 sec to 9 sec, then stays constant until 10 sec. What is the instantaneous velocity of the caterpillar at time t=6 st=6\text{ s} t=6 s t, equals, 6, start text, space, s, end text ?