What is the period of revolution about the Sun for an asteroid with a semimajor axis of 3 AU in the middle of the asteroid belt?

The period of revolution is 5.2 years.

Explanation:

The period of revolution about the Sun for an asteroid can be found using Kepler's third law:                                                                          

  (1)

Where:

p: is the period =?

a: is the semimajor axis (average distance from Sun) = 3 AU

By entering "a" value into equation (1) we have:

Therefore, the period of revolution about the Sun for an asteroid in the middle of the asteroid belt is 5.2 years.

I hope it helps you!

it is a negative acceleration