@cmonBruh You would be required to complete it once you arrive at the University. When it comes to University, there are very few things that are truly impossible; this is not one of those things. They are there to help you and will not reject someone based on a mere requirement that can be taken after admission. As long as you make a strong case for admission in other areas such as GPA, personal statement, etc., then you have a good chance. Are you transferring from a California CC? 90% of transfer students accepted to UCSD are from California CC’s and, if I remember correctly, 50% of transfer applicants are accepted (averaged across majors. It is different depending on major). Don’t let it get you down on your chances. I got in on a 2.85 for philosophy. Granted, its not nearly as competitive as a major like chem, but it shows that they are flexible in their requirements.
If you’re really that concerned, you could try and talk to admissions and your local CC about cross enrollment to take the course now (if you already live in the SD area, or close to it), or find another CC that offers a class equivalent to PHYS 2B. Or talk to your councilor at your CC about cross enrollment at a local university (usually CCs has some sort of agreement with the closest UC for situations like this one) for a course that is equivalent to PHYS 2B, transfer it to your CC after you complete it, and then you will have it done. Hope this helps!