A very long (length ) cylindrical galaxy is made of uniformly distributed mass and…
PHYSICS · Single correct · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A very long (length L) cylindrical galaxy is made of uniformly distributed mass and has radius R (R≪L). A star outside the galaxy is orbiting the galaxy in a plane perpendicular to the galaxy and passing through its centre. If the time period of star is T and its distance from the galaxy's axis is r, then:
(1) T∝r
(2) T∝r
(3) T∝r2
(4) T2∝r3