Quick Question about Rotational Energy

AI Thread Summary
The discussion centers on calculating the angular momentum and rotational energy of two astronauts connected by a rope in space. The angular momentum is determined to be 4573.8 kgm²/s. A participant questions the formula for rotational energy, initially using Krot = L²/(2I) but realizes a calculation error in determining the moment of inertia (I). The correct moment of inertia should be calculated based on the astronauts' mass and distance from the center of mass. The conversation highlights the importance of accurate calculations in physics problems.
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Two astronauts (Fig. P11.51), each having a mass of 77.0 kg, are connected by a 11.0 m rope of negligible mass. They are isolated in space, orbiting their center of mass at speeds of 5.40 m/s.


(a) Treating the astronauts as particles, calculate the magnitude of the angular momentum.
4573.8 kgm2/s
(b) Calculate the rotational energy of the system.

What is the equation for rotational energy of a system...I thought it was Krot = L^2/(2I) which for this problem would have been (4573.8^2)/(2 x 144 x 5.5^2) but this is not correct. I though 2 I would be equal to 2MR as the astronauts are like a hollow disk rotating in the air
 
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wow..never mind 2x77 is 154 and not 144 lol

thanks for looking
 
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