A particle passes a point A A\,A with speed u m s−1u\text{ m s}^{-1}u m s−1 and moves with constant acceleration a m s−2a\text{ m s}^{-2}a m s−2. It passes point BBB, 45 m from AAA, after 3 s and point CCC, 147 m from AAA, after 7 s.
Find u u\,u and aaa.
Determine whether the particle ever comes to instantaneous rest after passing AAA. Justify your answer.