[katieHaylor (OP)]

Mel asks:

If an asteroidal body (let’s say the size of a grapefruit) that was very dense came into contact with another asteroidal body the size of a grain of sand what would be the outcome?

Can you help?

[chiralSPO]

That will depend on their relative velocities and how hard they are.

The most likely outcome is that they just bounce off of each other (the grapefruit sized rock probably won't change its trajectory much, while the sand grain will change a lot--we can derive this by considering conservation of momentum.

Another possibility is that they stick together.

Another possibility is that they stick together but the impact blasts out a piece (or pieces) of them.

Another possibility is that they bounce off of each other AND one or both of them break into smaller pieces.