I’m going through PR right now and I stumbled upon this problem (#12):
http://gyazo.com/dfb71ef300114f1de9b5ffcfb59b70d5
The explanation they provide is pretty confusing:
http://gyazo.com/a63faaaf1037d14d4a7d4abb28212636
I got D as well but I’m thinking my reasoning may have been off. My logic was that the slope between A and D was the greatest whereas PR is saying it’s because the velocity changes the most at D because it “quickly decreases towards zero”. I can’t really see how it’d be quickly decreasing at D any more quickly than it’s increasing at C.
The derivative of a position vs time graph is the velocity. and the velocity of a position graph is the slope.
@pokemon1 Well yes, I’m aware of that. But how do I distinguish between where the acceleration would be the greatest? Why is it D though exactly? Is it consider D the exact point whereby the velocity switches from super positive to super negative? What if points D or E weren’t on the graph? How would I know where the greatest change in velocity is then?
Is the change in velocity relative to the previous point on the graph or the starting point, is essentially what I’m asking.
@bringit1 Try sketching the velocity-vs-time graph. Of course this is supposed to be more of a conceptual question (no calculation of derivatives needed) so I wouldn’t worry too much about “exact” points.
@MITer94 Ah I sort of see it now. It kind of starts at 0 goes up goes up a bit and stays constant and then spikes to zero at D. Thanks.