Question

http://extranet.redeemer.ab.ca/sites/Schools/hta/kcoderre/Physics%2020%20Notes%20and%20Assignments/Unit%201%20Kinematics/Lesson01%20Position%20Displacement%20and%20Velocity%20Worksheets.pdf

Answer 1

13

Answer 2

they gave the answers but i dont know how they got

Answer 3

13?
We have that, for some linear velocity, the average is:
\[
\frac{v_0+v_1}{2}=v_{\text{avg}}
\]So, for each segment we compute:
\[\begin{align}
\frac{0+40}{2}&=20\\
\frac{40+40}{2}&=40\\
\frac{40+80}{2}&=60
\end{align}\]The average velocity, for some change in time \(\Delta t_n\), average velocity of segment \(i\) as \(v_i\), and total time \(t\), we have:
\[
\frac{1}{t}\sum_{i=0}^n\Delta t_iv_i=v_{avg}
\]So:
\[
\frac{1}{60}(20\cdot20+40\cdot30+60\cdot10)=36.\bar6
\]Et voilá.