Getting into an engineering or physics graduate program with a C in Calculus 1 and 2
Graduate admissions are generally based on a complete record, and depend less on the details of specific courses than they do on an evaluation of your potential for success. You need to build that complete record and a few C's are a negative factor that you need to overcome. There are various ways to do that. One is to just move on and do better, perhaps learning more about calculus on your own, perhaps just taking more advanced courses and doing well there. 

If you continue to get C's in math it will be a problem. If you get good grades, especially in those subjects that use calculus it is less likely to matter. 

But even more important is to impress your professors with your hard work and potential. 

Short answer - the C's won't slam the door, but you need effective ways to open it wider.