Is the centripetal acceleration of Mars in its orbit around the Sun larger or smaller than the centripetal acceleration of the Earth?
On the average it is smaller, in the ratio
In the solar system, the star Sun's mass is the same for all orbiters. So, the centripetal acceleration is inversely proportional to the square of the distance.
The proportion for Mars in comparison with the Earth is (ratio of the inverse-squares of the average distances from the Sun) =
For the much smaller centripetal force, multiply this ratio by the ratio of the masses (0.642/5i97). The force ratio is 0.0463 = 1/21.6, nearly.
Data from NASA Planetary Fact Sheet.