Answer:
1) The girl's acceleration at time 't' is, [tex]a=0.47[/tex] m/s²
2) The girl's acceleration at time 't₁' is, [tex]a_{1}=0[/tex] m/s²
3) The girl's acceleration at time 't₂' is, [tex]a_{2}=-0.14[/tex] m/s²
Explanation:
Given data,
The initial walking speed of the girl, u = 0
The speed of the girl at the time 't' 3 s is, v₁ = 1.4 m/s
The time period the girl walked at the speed 1.4 m/s is, t₁ = 6 s
The girl slows down and comes to a stop during a period, t₂ = 10 s
1) The girl's acceleration at time 't'
[tex]a=\frac{v-u}{t}[/tex]
[tex]a=\frac{1.4-0}{3}[/tex]
[tex]a=0.47[/tex] m/s²
2) The girl's acceleration at time 't₁'
[tex]a_{1} =\frac{v_{1} -v}{t_{1}}[/tex]
[tex]a_{1}=\frac{1.4-1.4}{6}[/tex]
[tex]a_{1}=0[/tex] m/s²
3) The girl's acceleration at time 't₂'
[tex]a_{2} =\frac{v_{2} -v_{1}}{t_{2}}[/tex]
[tex]a_{2}=\frac{0-1.4}{10}[/tex]
[tex]a_{2}=-0.14[/tex] m/s²