The random vector \((X, Y)\) is defined as follows: \(X\) is uniformly distributed in the interval \([0,10]\). On condition \(X=x\), the random variable \(Y\) is uniformly distributed in the interval \([0, x]\). Determine

(1) \(f_{X, Y}(x, y), f_{X}(x \mid y)\), and \(f_{Y}(y \mid x)\),

(2) \(E(Y), E(Y \mid X=5)\), (3) \(P(5 \leq Y<10)\).