A child slides down a smooth slide from rest, starting at a height of 5 m. Ignoring friction and taking g = 10 m/s², the velocity at the bottom is approximately:

By conservation of energy on a smooth slide, PE at top = KE at bottom. mgh = ½mv², so v = √(2gh) = √(2 × 10 × 5) = √100 = 10 m/s. Notably, the result doesn't depend on the child's mass — heavier and lighter children reach the bottom at the SAME speed (ignoring friction).