theres a standard question about the spinning dancer who pulls her hands inward reducing her moment of inertia and increasing her ang. velocity . it seems she had to do some work against the centrifugal force (from momentum and energy equations)(adsbygoogle = window.adsbygoogle || []).push({});

i thought of a simpler example to check if the amt of work that needs to be done agianst the force is indeed equal to the change in energy .considering a particle insted of the ballerina moving in a circle i worked out the work necassary using integral of force times distance moved . i substiuted values for ang. vel. since it isnt constant(from cons of ang momentum eq.) and it worked out to be a logarthmic expression . the change in energy from the first approach was different( no log term) . i have a feeling i have made some fundamental mistake . the calculations seem ok.,

govinda

--------------------------------------------------

"if its you against the world bet on the world "

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

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

# Working out energy change during change of moment of inertia

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