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A uniform, solid sphere of mass 3.2 kg and diameter 63 cm is rotating about its diameter at 230 rev/min. What is the kinetic energy of rotation?
230rev/min= 24.1 rad/s
I know that KE=1/2Iw^2 and interia of a solid sphere is I=2/5MR^2
I=(2/5)(3.2)(.63)^2
=.508032
KE=(1/2)(.508032)(24.1)^2
=147.5 J
For some reason my answer is wrong. Am I missing something? What am I doing wrong?
230rev/min= 24.1 rad/s
I know that KE=1/2Iw^2 and interia of a solid sphere is I=2/5MR^2
I=(2/5)(3.2)(.63)^2
=.508032
KE=(1/2)(.508032)(24.1)^2
=147.5 J
For some reason my answer is wrong. Am I missing something? What am I doing wrong?