a) $\left[ {2a = 3.5} \right]$

Acceleration is $1.75{\text{ }}m{s^{ - 2}}$

$\left[ {1.75 = g\sin \alpha } \right]$ or

$[0.5 \times {3.5^2} = gh;{\text{ }}s = 0.5 \times 3.5 \times 2$ and

$\sin \alpha  = h/s]$

Angle is ${10.1^ \circ }$ or ${0.176^ \circ }$

b) $\left[ {{s_P} = {\raise0.5ex\hbox{$\scriptstyle 1$}
\kern-0.1em/\kern-0.15em
\lower0.25ex\hbox{$\scriptstyle 2$}}a{2^2} + \{ \left( {a2} \right)t + {\raise0.5ex\hbox{$\scriptstyle 1$}
\kern-0.1em/\kern-0.15em
\lower0.25ex\hbox{$\scriptstyle 2$}}a{t^2}\} } \right]$

or $\left[ {{s_P} = {\raise0.5ex\hbox{$\scriptstyle 1$}
\kern-0.1em/\kern-0.15em
\lower0.25ex\hbox{$\scriptstyle 2$}}a{{\left( {t + 2} \right)}^2}} \right]$

$\left[ {{s_P} - {s_Q} = {\raise0.5ex\hbox{$\scriptstyle 1$}
\kern-0.1em/\kern-0.15em
\lower0.25ex\hbox{$\scriptstyle 2$}}a{2^2} + \left( {a2} \right)t + {\raise0.5ex\hbox{$\scriptstyle 1$}
\kern-0.1em/\kern-0.15em
\lower0.25ex\hbox{$\scriptstyle 2$}}a{t^2} - {\raise0.5ex\hbox{$\scriptstyle 1$}
\kern-0.1em/\kern-0.15em
\lower0.25ex\hbox{$\scriptstyle 2$}}a{t^2}} \right]$

$2 \times 1.75 + 2 \times 1.75t$

$\left[ {4.9 = 2a + 2at} \right]$

$t = 0.4$