3 A particle \(P\) travels in a straight line. The velocity of \(P\) at time \(t\) seconds after it passes through a fixed point \(A\) is given by \(\left( 0.6 t ^ { 2 } + 3 \right) \mathrm { ms } ^ { - 1 }\). Find
- the velocity of \(P\) when it passes through \(A\),
- the displacement of \(P\) from \(A\) when \(t = 1.5\),
- the velocity of \(P\) when it has acceleration \(6 \mathrm {~ms} ^ { - 2 }\).