If you excelled in the content in the first exam then you wouldn't have needed a formula sheet most likely. Not sure if this applies to second year Mech Engineering, but definitely in first year engineering dynamics for any topics that I excelled at, I remembered any relevant equations.
Which brings me to my next point, the course being Mech Eng means that the content will be the same as the first exam (at least from my somewhat limited experience). Obviously they won't give the same questions, but it's not a degree like commerce where there are a range of concepts and theories to remember and they might only test a few of these in the exam.