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One- half the acceleration due to gravity Nothing that the tension in the rope i

ID: 1986744 • Letter: O

Question

One- half the acceleration due to gravity Nothing that the tension in the rope is not the same on each side of the pulley, find the mass of the pulley. Rotational Work and Energy. Calculate the kinetic energy that the earth has because of its rotation about its own axis and its motion around the sun. Assume that the earth is a uniform sphere and that its path around the sun is circular. For comparison, the total energy used in the United States in one year is about 1.1 times 10 20 J. A flywheel is a solid disk that rotates about an axis that is perpendicular to the disk at its center Rotating flywheels provide a means for storing energy in the form of rotational kinetic energy and possible alternative to batteries in electric

Explanation / Answer

Mass of the earth M = 5.98*10^24 Kg

Radius of the earth R = 6.38*10^6 m

(a)

The rotational kinetic energy of the earth K = (1/2)I^2

                                                                = (1/2)(2/5)MR^2 (2/T)^2

                                                                = (1/5)(5.98*10^24)(6.38*10^6)^2(2/24*3600)^2

                                                                 = 2.57*10^29 J

(b)

Radius of the orbit R = 1.5*10^11 m

The rotational Kinetic energy of the earth - sun system

                                       K = (1/2)I^2

                                          = (1/2)(MR^2)(2/T)^2

                                          = 0.5 * 5.98 * 10^24 * (1.5*10^11)^2 (2/24*3600)^2          

                                          = 2.66*10^33 J