Assertion: racket's mass | /r/HasProperty | equal
Facets:
value: to the mass of the ball
type: OTHER
Source sentences:
text: The reason is that the effective mass of the racquet at that point is equal to the mass of the ball.
text: This is due to the fact that the effective mass of the racket at the dead spot — usually close to the tip — is equal to the mass of the ball.