a/ Có \(\Delta S_6=v_0.6+\frac{1}{2}.a.6^2-v_0.5-\frac{1}{2}a.5^2=14\)
\(\Leftrightarrow\frac{25}{9}+5,5a=14\)
\(\Leftrightarrow a\approx2,04\left(m/s^2\right)\)
b/ \(S=v_0t+\frac{1}{2}at^2=\frac{25}{9}.20+\frac{1}{2}.2,04.20^2\approx463,5\left(m\right)\)