A galaxy in a cluster has a crossing time of 2.3 Gyr. Given that the diameter of the cluster is 2.5 Mpc, calculate the average velocity of the galaxy in the cluster.

You find a small satellite galaxy orbiting 66 kpc from the center of a larger galaxy at a speed of 210 km/s. What is the total mass of the galaxy-satellite galaxy system? (Give your answer in terms of MSun.)

A galaxy is observed to recede at speed 140 km/s. If the Hubble constant is 70 km/s/ Mpc, how far is the galaxy?

Please don't provide handwritten solution ...

Figure 2 shows the "rotation curve" of NGC 2742. It plots the “radial velocity (V)" (how fast material is moving either toward or away from us) that is measured for objects at different distances (R = radius") from the center of the galaxy. The center of the galaxy is at 0 kpc (kiloparsecs) with a speed of 9 km/sec away from us. (These velocities have been corrected for the observed tilt of the galaxy and represent true orbital velocities of the stars and gas.) 200 100 U4779 -100 As you can see, one side of the galaxy is moving with a negative velocity (spinning toward us), while the other side has a positive velocity (spinning away from us). Using Newton's gravity equation, we will be able to determine the gravitational mass of the entire galaxy and how the mass varies versus distance from the galaxy's center. -200 -8 8 -4 Radius (kpc) Read the following text carefully and follow the instructions: Select five radii spaced evenly from 0-10 kpc across the galaxy. Your selections should…

Compute the critical density of the universe using the universal gravitational constant G= 6.67*10-11Nm2/kg2 and the Hubble constant of 73km/s/Mpc. B) What is the geometrical implication be if the universe has the critical density? Note: 1pc = 3.1*1016m