(a) Using the conservation of momentum, the initial momentum of the system is given by:

\(5 \times 8.5 + 3 \times 0 = 5 \times 0.25v + 3v\)

Solving for \(v\), we have:

\(5 \times 8.5 = 5 \times 0.25v + 3v\)

\(42.5 = 1.25v + 3v\)

\(42.5 = 4.25v\)

\(v = 10 \text{ m/s}\)

Thus, the speed of B after the collision is 10 m/s.

(b) The initial kinetic energy (KE) of the system is:

\(\text{KE before} = \frac{1}{2} \times 5 \times 8.5^2 = 180.625 \text{ J}\)

The kinetic energy after the collision is:

\(\text{KE after} = \frac{1}{2} \times 5 \times 2.5^2 + \frac{1}{2} \times 3 \times 10^2\)

\(= 15.625 + 150 = 165.625 \text{ J}\)

The loss of kinetic energy is:

\(\text{KE loss} = 180.625 - 165.625 = 15 \text{ J}\)