Whips and combat maneuvers.

[bigrig107]

Can you perform combat maneuvers with a whip even if not proficient?
Do they take the non-proficient penalty?

[CountofUndolpho]

Yes and yes.
The only penalty (unless otherwise stated c.f. Bastard Sword) for a lack of proficiency is the -4 penalty. If you are attempting a Combat Manoeuver that replaces an Attack with that weapon then the penalty will apply.

So for whip, in the case of disarm the penalty would only be -2 but for trip it would be -4 to CMB and so on.

[bigrig107]

Why the -2?

[blackbloodtroll]

Disarm: When you use a disarm weapon, you get a +2 bonus on Combat Maneuver Checks to disarm an enemy.