$(1)\cdot (2)$
$(a)$
日本語表記: 速度,英語表記: velocity
$(b)$
日本語表記: 加速度,英語表記: acceleration
$(3)$
\[\begin{align}
x
&=R\cdot \cos\theta + L\cdot \cos\phi\\
&=R\left(\cos\theta + \frac{L}{R}\cos\phi \right)
\end{align}\]
\[
R\cdot \sin\theta = L\cdot \sin\phi \ より \ \sin\phi=\frac{R}{L}\sin\theta\\
\]
\[\begin{align}
\cos\phi
&=\sqrt{1-\sin^2\phi} \\
&=\sqrt{1-\left(\frac{R}{L}\right)^2 \sin^2\theta}\\
&\fallingdotseq1-\frac{1}{2}\left(\frac{R}{L} \right)^2 \sin\theta
\end{align}\]
\[
よって、x=R \left[ \cos\theta +\frac{L}{R}\left\{1-\frac{1}{2} \left(\frac{R}{L} \right)^2 \right\}\sin^2\theta \right]
\]
\[
\therefore
x=R \left( \cos\theta +\frac{L}{R}-\frac{1}{2}\cdot\frac{R}{L}\sin^2\theta \right)
\]
$(4)$
\[\begin{align}
\frac{dx}{dt}
&=\frac{d}{dt}\left\{R\left(\cos\theta +\frac{L}{R} - \frac{1}{2}\cdot \frac{R}{L} \cdot \sin^2\theta \right) \right\}
\end{align}\]
\[\sin^2\theta=\frac{1}{2}\left(1-\cos2\theta\right) \ より、\]
\[\begin{align}
&=\frac{d}{dt}\left\{R\left(\cos\theta +\frac{L}{R} - \frac{1}{2}\cdot \frac{R}{L} \cdot \frac{1}{2}\cdot \left(1-\cos2\theta\right) \right) \right\}\\
\end{align}\]
\[
\theta = \omega t より、
\]
\[\begin{align}
&=\frac{d}{dt}\left[R\left\{\cos\omega t +\frac{L}{R} - \frac{1}{2}\cdot \frac{R}{L} \cdot \frac{1}{2} \left(1-\cos2\omega t \right)\right\} \right]\\
&=R \left\{-\omega \cdot \sin\omega t -\frac{1}{4}\cdot \frac{R}{L}\left(2\omega \cdot \sin2\omega t \right)\right\}
\end{align}
\]
\[
\therefore
v=-R\omega \left(\sin\omega t +\frac{1}{2}\cdot \frac{R}{L} \cdot \sin2\omega t \right)
\]
$(5)$
\[\begin{align}
\frac{dv}{dt}
&=\frac{d}{dt}\left\{-R\omega \left(\sin\omega t +\frac{1}{2}\cdot \frac{R}{L} \cdot \sin2\omega t \right)\right\}\\
&=-R\omega \left(\omega \cdot \cos\omega t +\frac{1}{2}\cdot \frac{R}{L}2\omega \cdot \cos2\omega t \right)
\end{align}\]
\[
\therefore
a =-R\omega^2 \left(\cos\omega t + \frac{R}{L} \cdot \cos2\omega t \right)
\]
$(6)$
\[\begin{align}
v
&=-50\,\rm{mm}\times 100\,\rm{rad/s}\left(\sin45^\circ +\frac{1}{2}\cdot \frac{50\,\rm{mm}}{200\,\rm{mm}}\cdot \sin\left(2\times45^\circ \right) \right) \\
&=-4160\ \rm{mm/s}
\end{align}\]
\[
\therefore
v=-4.16\ \rm{m/s}
\]
\[\begin{align}
a
&=-50\,\rm{mm}\times \left( 100\,\rm{rad/s} \right)^2\left(\cos45^\circ + \frac{50\,\rm{mm}}{200\,\rm{mm}}\cdot \cos\left(2\times45^\circ \right) \right) \\
&=-3.535\times10^5\ \rm{mm/s^2}
\end{align}\]
\[
\therefore
a =-354\ \rm{m/s^2}
\]