Which of the following statements is true? a. pressure flattened the solar nebula into a disk and as it contracted its rotation rate decreased. b. pressure flattened the solar nebula into a disk and as it contracted its rotation rate increased. c. gravity flattened the solar nebula into a disk and as it contracted its rotation rate decreased. d. gravity flattened the solar nebula into a disk and as it contracted its rotation rate increased.

The following statement is true among the given options: Gravity flattened the solar nebula into a disk and as it contracted its rotation rate increased.

The nebula planate as a outcome of collisions between particle, therefore changing the dynamics between the motion i.e.  haphazard motions into systematic ones.  

The nebular started with a little rotation and as the clouds contracted, it started to spin faster. The attraction between particles became brawny as the nebula contracted, therefore increasing the speed of the process.

Therefore the correct option is (D)

the average speed is 24.57 km/hr

false br