Question

1. A racing car starts from rest at the first pole and accelerates \( 0.4 \mathrm{~m} / \mathrm{s}^{2} \) for 10 seconds, continues at constant velocity for 20 seconds and stopped in the last pole in 6 sec . with constant deceleration. If the spacing between the poles is 4 meters apart, how many poles are there? The race track is parallel to the rows of poles. \[ \begin{array}{rlrl} S & =V_{0} t+\frac{1}{2} a t^{2} & S=V_{0} t+\frac{1}{2} a t^{2} & V_{F}=V_{0}+a t \\ & =0+\frac{1}{2}(0.4)(10)^{2} & & =(4)(20)+0 \\ & =20 \mathrm{~m} & & 0=4+a(6) \\ & -80 \mathrm{~m} & \frac{-4}{6}=\frac{a(6)}{6} \\ V_{F} & =V_{0}+a t & V_{F}=4 \mathrm{~m} / \mathrm{s} & a \\ & =0+(0.4)(10) & & S=-0.67 \\ & =4 \mathrm{~m} / \mathrm{s} & & \\ & & & =4(6)+\frac{1}{2}(-0.67)(6)^{2} \end{array} \] Total Distance : \[ \begin{array}{l} S=20 m+80 m+12 m=112 m \\ \text { H of poles }=\frac{112}{4}+1=28+1-29 \text { poles } \end{array} \]

          1. A racing car starts from rest at the first pole and accelerates \( 0.4 \mathrm{~m} / \mathrm{s}^{2} \) for 10 seconds, continues at constant velocity for 20 seconds and stopped in the last pole in 6 sec . with constant deceleration. If the spacing between the poles is 4 meters apart, how many poles are there? The race track is parallel to the rows of poles.
\[
\begin{array}{rlrl}
S & =V_{0} t+\frac{1}{2} a t^{2} & S=V_{0} t+\frac{1}{2} a t^{2} & V_{F}=V_{0}+a t \\
& =0+\frac{1}{2}(0.4)(10)^{2} & & =(4)(20)+0 \\
& =20 \mathrm{~m} & & 0=4+a(6) \\
& -80 \mathrm{~m} & \frac{-4}{6}=\frac{a(6)}{6} \\
V_{F} & =V_{0}+a t & V_{F}=4 \mathrm{~m} / \mathrm{s} & a \\
& =0+(0.4)(10) & & S=-0.67 \\
& =4 \mathrm{~m} / \mathrm{s} & & \\
& & & =4(6)+\frac{1}{2}(-0.67)(6)^{2}
\end{array}
\]

Total Distance :
\[
\begin{array}{l}
S=20 m+80 m+12 m=112 m \\
\text { H of poles }=\frac{112}{4}+1=28+1-29 \text { poles }
\end{array}
\]

1. A racing car starts from rest at the first pole and accelerates 0.4 m / s^2 for 10 seconds, continues at constant velocity for 20 seconds and stopped in the last pole in 6 sec . with constant deceleration. If the spacing between the poles is 4 meters apart, how many poles are there? The race track is parallel to the rows of poles.

S =V0 t+(1)/(2) a t^2 S=V0 t+(1)/(2) a t^2 VF=V0+a t
=0+(1)/(2)(0.4)(10)^2 =(4)(20)+0
=20 m 0=4+a(6)
-80 m (-4)/(6)=(a(6))/(6)

VF =V0+a t VF=4 m / s a
=0+(0.4)(10) S=-0.67
=4 m / s
=4(6)+(1)/(2)(-0.67)(6)^2

Total Distance :

S=20 m+80 m+12 m=112 m
H of poles =(112)/(4)+1=28+1-29 poles

Added by Lisa B.

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