A curve \(C\) has a parametric equations
\(x=5{{t}^{2}}\), \(y=2t\).
Find the value of \(t\) at the point on \(C\) where the tangent has gradient \(0.8\).
The normal at the point \(P\left( 5{{p}^{2}},2p \right)\) on \(C\) meets the \(x-\)axis at point \(Q\). Find the Cartesian equation of the locus of the mid-point of \(PQ\) as \(p\) varies.