Answer:
[tex]\begin{gathered} (a)\Rightarrow v=2ms^{-1} \\ (b)\Rightarrow v=1ms^{-1} \\ (c)\Rightarrow v=6.67ms^{-1}_{} \\ (d)\Rightarrow v=1.2ms^{-1} \\ (e)\Rightarrow v=0ms^{-1} \end{gathered}[/tex]
Explanation: We need to calculate the speed on intervals a b c d and e, the speed can be calculated with the following formula:
[tex]v=\frac{\Delta S}{\Delta t}\Rightarrow(1)[/tex]
(a) 0-5 seconds Interval:
[tex]\begin{gathered} v=\frac{\Delta S}{\Delta t}\Rightarrow v=\frac{(10m-0m)}{(5s-0s)}=\frac{10m}{5s}=2ms^{-1} \\ v=2ms^{-1} \end{gathered}[/tex]
(b) 5-15 seconds Interval:
[tex]\begin{gathered} v=\frac{\Delta S}{\Delta t}\Rightarrow v=\frac{(20m-10m)}{(15s-5s)}=\frac{10m}{10s}=1ms^{-1} \\ v=1ms^{-1} \end{gathered}[/tex]
(c) 15-18 seconds Interval:
[tex]\begin{gathered} v=\frac{\Delta S}{\Delta t}\Rightarrow v=\frac{(40m-20m)}{(18s-15s)}=\frac{20m}{3s}=6.67ms^{-1} \\ v=6.67ms^{-1} \end{gathered}[/tex]
(d) 18-23 seconds Interval:
[tex]\begin{gathered} v=\frac{\Delta S}{\Delta t}\Rightarrow v=\frac{(46m-40m)}{(23s-18s)}=\frac{6m}{5s}=1.2ms^{-1} \\ v=1.2ms^{-1} \end{gathered}[/tex]
(e) 23-25 seconds Intervals:
[tex]\begin{gathered} v=\frac{\Delta S}{\Delta t}\Rightarrow v=\frac{(40m-40m)}{(25s-23s)}=\frac{0m}{2s}=0ms^{-1} \\ v=0ms^{-1} \end{gathered}[/tex]
