This is the SOLUTIONS for my one page worksheet with 9 different versions of the same 3 projectile problems. The preview shows the solutions for one group (the pigs). The file includes all 9 pages of solutions - one for each group.
I use this as a homework or in-class assignment for my physics classes. Students solve problems alone, then meet in groups to compare answers. When groups don't agree, I give them a laminated copy of their group's solutions.
I vary the frame of references - UP is not always the positive direction for my solutions.....but of course we will get the same numerical answer if your students always use up as positive and g = - 9.8.