Pretty sure its volcanic ash or magma, hope this helps
<span>So we want to know how did the planets form in the Solar system. So the current most accepted explanation is accretion. First the Sun formed, and what has left was a disk made out of gas and dust which later formed the planets trough attractive gravitational force.</span>
The ball rolled a distance of
d = 12m + 20m.
But the change of position is
x = + 12m - 20m