Lightly knock then violently corral vehicle with force (6,3)
I believe the answer is:
patrol car
'vehicle with force' is the definition.
(police force vehicle)
'lightly knock then violently corral' is the wordplay.
'lightly knock' becomes 'pat'.
'then' says to put letters next to each other.
'violently' indicates anagramming the letters.
'corral' with letters rearranged gives 'rolcar'.
'pat'+'rolcar'='PATROL CAR'
(Other definitions for patrol car that I've seen before include "Police vehicle" , "Panda, maybe" .)