(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 .

i don't know, you need to give me some answers.

explanation:

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​