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:
A45 m/s
B5 m/s
C20 m/s
D10 m/s
Answer & Solution
Correct answer: D. 10 m/s
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).
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