Vaisesika Sūtra 5.1.07

संयोगाभावे गुरुत्वात् पतनम् ॥७॥

saṁyogābhāve gurutvāt patanam ॥7॥

[संयोग-अभावे (saṁyoga-abhāve) - in absence of conjunction; गुरुत्वात् (gurutvāt) - due to gravity; पतनम् (patanam) - falling;]

In the absence of conjunction, falling occurs due to gravity.