A 35.9 kg child starting from rest slides down a water slide with a vertical height of 20.3 m. (Neglect friction.)What is the child speed half way down

Answer 1

PE at top: mgh = 35.9*9.8*20.3 = 7142 J
She loses half that on the way down.

KE = 1/2 mv^2 = 3571
So, v^2 = 3571/35.9 = 99.47
Call it 100
So, v = 10