Hello there, this is my first posting on this board. I am a third year physics major and I've taken a lot of courses but I've always just scraped by with a large amount of help from small groups. I'm thinking about reconsidering my major because I feel like I no longer can understand the concepts.. but anyways, I came across this problem and I am stumped.(adsbygoogle = window.adsbygoogle || []).push({});

Using {r, phi, z} coordinates write the equation of motion for a small block that is free to move on the inside surface of an upper cone under the influence of gravity. Repeat this problem with the addition of simple friction.

I have done the free body diagram but I don't know how to post that on here. Anways this is what i got:

r^=-Ncos(phi)=-mv^2/r

z^=Nsin(phi)-mg=0

Then divide z^ by r^ and get this:

tan(phi)=rg/(v^2)

???

I really have no idea what I am doing. Any help or sense of direction would be greatly appreciated.

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

Dismiss Notice

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!

# Block sliding on the inside of a cone

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