Watch another video series on kinematics

answer key to the Average velocity Section 8.2 is here  please note that the page numbers ought to be noted to understand the answer key.  correction on answer key:  page 158 #3c should say that A is faster because it is a steeper slope

If the teacher doesn't put it on the projector, then try watching it on your phones.  Click on the series  here  and watch the examples of how to answer the questions.
And then try these questions here and check them against the answer key.

the answer key to the calcuations on the questions are below: note correction on number 4

1. displacement = final position – initial position.
   ∆d= df- di The df= 7cm and di = 5cm.
   ∆d= 7 cm – 5 cm
   ∆d= 2 cm
2. Average velocity is equal to displacement over time
   ∆v= ∆d/ ∆t first, ∆d=df-di ∆d= 1200m – 150m = 1050m.
   Next the time is 30 minutes but we measure this in seconds so
   30 min = 30 min x 60s/min = 1800s so
   ∆v= ∆d/ ∆t
   ∆v= 1050 m/1800s
   ∆v= o.583 m/s
3. 5.2 m/s is not walking velocity, it's running velocity.
4. Calculating m/s so these are the equations you need:
   ∆v= ∆d/ ∆t and since ∆d=df-di, then ∆v= ( df-di) / ∆t
   So ∆v= ∆d / ∆t
   19m/h = ∆d / .53h
   solve for ∆d 19miles  x  .53h = 10.07miles
5. She ran around a track and her ∆d =0. Therefore her velocity would be 0 as well
6. ∆d = 0 but we are now calculating speed d or total distance is 561m and the speed of sound is 340 m/s
   s = total distance/time therefore
   time = total distance/speed s= 561m and total distance is 561m
   time = 561m/340m/s
   time = 1.65 s
7. B
8. F
9. D
10. A
11. E
12. G
13.