# Kinetic and Rotational energy of a sphere

by hyddro
Tags: energy, kinetic, rotational, sphere
 Emeritus Sci Advisor HW Helper PF Gold P: 7,819 The mass is 0.32kg, not 0.032kg, but that shouldn't affect the ratio. Maybe you have too much round-off error. .3 is about 5% different than the correct answer.
 P: 74 ok but am i doing this correctly? i mean, am i supposed to divide Krot by Krolling to get a ratio? or is it the other way (Kroll/krot) ? I don't get it, no matter how i do it, i am still getting around 0.29... and when round i get 0.3 but it's wrong :/
 Emeritus Sci Advisor HW Helper PF Gold P: 7,819 Kinetic and Rotational energy of a sphere The fraction of the kinetic energy that is rotational is what you are calling Krot / Kroll . Why are you rounding to 1 significant figure?
 P: 74 i am rounding to two sig figures :( 0.30, cause i get 0.298
 P: 74 please i really need to understand this, i am not getting the answer.. :/
 P: 294 The question is What fraction of its kinetic energy is rotational?, your answer is the relationship between the rotational and translational kinetic energies.
 P: 74 ok, i dont know what that means then, i thought you had to get the ratio between them,,, if so then i am getting 0.30, which is supposed to be wrong...
Emeritus