At the instant shown in figure 3, the blocks are moving toward each other with the same speed of 0. 35m/s. The blocks collide 0. 50 seconds later. What is the speed of the two-block system’s center of mass just before the blocks collide?.

The answer would be true!

It depends on the subject for me. some exams are easier than others so i usually go through it and answer questions i know based on my general knowledge, then double check after. going through the lesson can a lot  because the exams can be  very lesson-specific, but sometimes they are ridiculously long so a lot of people don't take the time. i did find that, when i went through the lessons, i was making 100's on my exams vs strictly using + the internet and  i make 90's.