A Rotation Curve Is a Plot of the Rotational Velocity

question 45

Multiple Choice

A rotation curve is a plot of the rotational velocity of a galaxy as a function of the distance away from the galactic center. What does the rotation curve of the Milky Way Galaxy look like?

• A) The curve is a straight line, slanted upward, suggesting that the velocity increases linearly with radius.
• B) The curve rises steeply, levels off, and then experiences the "Keplerian falloff" expected from Kepler's third law.
• C) The curve rises steeply and then oscillates up and down showing the effect of the spiral arms.
• D) The curve rises steeply, and then levels off or rises gradually until well beyond the edge of the visible galaxy.