It would be clearer if you gave more info on your role and audience. My assumption is that you are the engineering instructor, not calculus. It sounds like they are already getting introduction to derivatives in calculus, no?
My advice would NOT be to obsess about limits and such (leave that to the formal calculus class). Keep the discussion geared to slope of a curve and some simple physical examples (position, speed, acceleration). [IOW, use of calculus in engineering.]
But again, it is hard to advise you, since you are imprecise in the question about the situation. What course are you teaching with them, are you only giving one lecture and then why the heck. What is going on in their physics classes. Etc.
EDIT: You do too know about MESE since you asked a question there on 11FEB. Maybe you aren't keeping track of the different stacks? But you have asked once before something at MESE. Note that that time, you also didn't give enough explanation of the situation.
FURTHER EDIT: And in both cases, I get impression that you are wanting to substantially remediate calculus weaknesses (for example there you mentioned topics that were too hard for weak calculus students). This is not the ideal approach. You don't have the right students for that and worse you don't have the TIME for that, with these students. You need to take much more an approach of boiling things down to the absolute most essential things. "Bang for the buck". For here, start with the simplest, most important derivatives to take. Those being speed and accelleration of a quadratic equation of position (this allows you to do gravity F=MA problems.)