5 A particle moving in a straight line starts from rest at a point \(A\) and comes instantaneously to rest at a point \(B\). The acceleration of the particle at time \(t \mathrm {~s}\) after leaving \(A\) is \(a \mathrm {~m} \mathrm {~s} ^ { - 2 }\), where $$a = 6 t ^ { \frac { 1 } { 2 } } - 2 t$$

1. Find the value of \(t\) at point \(B\).
2. Find the distance travelled from \(A\) to the point at which the acceleration of the particle is again zero.