Hi all,(adsbygoogle = window.adsbygoogle || []).push({});

A roller-coaster train is upside down when it is at the top of a circular vertical structure which is 20 m high. In order to get to the top without falling out, the velocity of the roller-coaster train at the top of the circle has to be more than

a 25 m s-1

b 14 m s-1

c 9.9 m s-1

d zero

Ans : C

The question didn't give me any mass of anything at all to work with except for height. Is mass not required for this question? i couldn't get C, in fact i chose D, zero instead.

Any help will be greatly appreciated. ( probably need clarification of concepts.)

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Vertical Circular Motion

**Physics Forums | Science Articles, Homework Help, Discussion**