Merry-Go-Round

Classical Mechanics Level 1

A merry-go-round has a radius of about $8 \text{ m}$ . A child sitting on a horse on the outer edge sees his parents, standing still at the entrance, every $20 \text{ s}$ . If the child's horse could break free of its merry-go-round restraints and continue forward tangentially without accelerating, how fast would it be traveling in $\text{m}/\text{s}$ ?