(9) A dancer spins at 72rpm about an axis through the center with arms outstretched. The dancer mass=90kg, model the head as a uniform sphere r=8.0cm Model the trunk and legs as uniform solid cylinder r=12.0cm, arms as slender rods L=60.0cm. On the average the head=7%, both arms together=13% and trunk and legs=80% of body mass. Find the K. E. of the dancer note: arms are I around an axis for slender rod: 1/3ML^2 each arm note2: Moments of Inertia are summable, i. e. I total = I1 + I2 + I 3 +...

Explanation:

ω = angular velocity = 2π n = 2π x 72 / 60

= 7.536 rad /s

mass of head = 90 x .07 = 6.3 kg

moment of inertia of head = 2 /5 m R²

= .4 x 6.3 x .08²

= .016128 kg m²

moment of inertia of trunk + legs

= 1/2 m R²

= .5 x .8 x 90 x .12²

= .5184 kg m²

moment of inertia of arms

= 1/3 m L²

= 1 / 3 x .13 x 90 x .60²

= 1.404 kg m²

Total moment of inertia

I = 1.938 kg m²

kinetic energy = 1/ 2 I ω ²

where I is moment of inertia and ω is angular velocity

= .5 x 1.9338 x  7.536²

=55 J approx .

gans

explanation:

vestigial organs (like your appendix) are organs that no longer serve a purpose.

no sign of dia of fuel cell