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the andromeda galaxy is at a distance of 2.1x10^22m from our galaxy. The mass of

ID: 1316941 • Letter: T

Question

the andromeda galaxy is at a distance of 2.1x10^22m from our galaxy. The mass of Andromeda is 6x10^41kg and the mass of our galaxy is 4X10^41kg.

a.) gravity accelerates the galaxies toward each other. As reckoned in an inertial reference frame, what is the acceleration of andromeda? What is the acceleration of our galaxy? treat both galaxies as point particles.

b.) The speed of andromeda relative to our galaxy is 266km/s. What is the speed of andromeda and what is the speed of our galaxy relative to the center of mass of the two galaxies?

c.) what is the kinetic energy of each galaxy relative to the center of mass? what is the total energy (kinetic and potential) of the system of the two galaxies? Will the two galaxies eventually escape from each other?

Explanation / Answer

For part b use the formula m1v1+m2v2/m1+m2 (6x10^41 kg)(266000 m/s)/(10x10^41kg)= 1.60x10^5 m/s velocity of our galaxy is -1.6x10^5 m/s Velocity of andromeda= 2.66 x 10^5 m/s-1.60x10^5m/s=1.06x10^5m/s