I was able to figure out part c (by using -9.8 and the acceleration forumla), comes out to 2.55s, rounded to 2.6s. No problems there.A rock is thrown straight up into the air at a speed of 25m/s. After a period of 7s
a) Find the change in displacement of the rock. (65m [down])
b) Find the total distance the rock has travelled (130m)
c) How long does it take to get to the top? (2.6s)
For part a, I used Velocity average = delta d / delta t
(25+0)/2 = delta d / (2.6*2) I did get the right answer, but I dont fully understand the conceptual part if it, I keep thinking it should be 0, since it goes straight up and straight back down to starting point? Also why do you need a direction for the answer?
As for b), I never got to it, but I suppose for some reason, you need to double the answer for a to get it...
Lastly, I think the 7.0s is just there to throw people off?