Assertion: gravity's mass | /r/HasProperty | positive
Facets:
Source sentences:
text: The difference is because charge can be either positive or negative, while mass can only be positive.
text: He noted that two identical masses, one positive and one negative, placed near each other will therefore self-accelerate in the direction of the line between them, with the negative mass chasing after the positive mass.
text: Just as in classical physics, it can be shown that these masses are positive.