forcemode2d.impulse do we need time.deltatime?

If im using forcemode2d.impulse force on a rigidbody2d in FixedUpdate()

do i need to multiple the value by time.deltatime?

Impulse should be used if you want to apply a one-time impulse on the object like a jump for example. This is related to the physical impulse. A “force” has to be applied over a certain time. An impulse is the result of such a process. In Unity it’s the accumulated force which has been applied for one second.

So no, you shouldn’t use Time.deltaTime when applying an impulse on your object. However if you plan to apply a force every frame you shouldn’t use forcemode.impulse but either “force” or “acceleration”.

Impulse and velocitychange are ment for immediate one-time changes.