Question

A roller coaster is designed such that riders experience ''weightlessness'' as they go round the top of a hill whose radius of curvature is 20 m. The speed of the car at the top of the hill is between

• A. 16 m/s and 17 m/s
• B. 13 m/s and 14 m/s
• C. 14 m/s and 15 m/s
• D. 15 m/s and 16 m/s

Answer 1

Answer: (C)

14 m/s and 15 m/s

Answer 2

$mg=\frac{mv^2}{R}\Rightarrow v=\sqrt {Rg}$
$v=\sqrt{20\times10}=\sqrt{200}=14.1\,m/s$
i.e.. Between 14 and 15 m/s.