#2015_14 From an old Physics Olympiad!

Classical Mechanics Level 4

Consider a long solid, rigid hexagonal prism like a common type of pencil. The mass of the prism is M M and is uniformly distributed. The length of each side of cross-sectional hexagon is a a . The moment of inertia I I of the hexagonal prism about its central axis is I = 5 12 M a 2 I=\frac { 5 }{ 12 } M{ a }^{ 2 } Find the moment of inertia I I of the hexagonal prism about an edge of the prism.

Details and Assumptions :

  • M = 1 kg M=1 \text{ kg} , a = 1 m a=1 m
More questions .


The answer is 1.416.

Anandhu Raj by Anandhu Raj , 23, India

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

Potsawee Manakul
Aug 18, 2015

I ′ = I c m + M d 2 I'=I_{cm}+Md^{2} I ′ = 5 12 M a 2 + M a 2 I'=\frac{5}{12}Ma^{2} + Ma^{2} I ′ = 17 12 M a 2 I'=\frac{17}{12}Ma^2 I ′ = 17 / 12 I'=17/12

PS. This is a very tiny part of that IPhO problem; if anybody wants to solve the full problem, you can find it at IPhO 1998 Problem 1 (Iceland).

2 Helpful 0 Interesting 0 Brilliant 0 Confused
Utkarsh Tiwari
Jun 30, 2015

why have you named the problem as ipho problem it is 100 times diluted then the original. anandhu raj

0 Helpful 0 Interesting 0 Brilliant 0 Confused

Well,the root of problem is there.

Anandhu Raj - 5 years, 11 months ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...