What acceleration, to the nearest tenth of a m/s2, will the same net force cause on a 2.8 kg box?

The answer to this is 7.5. It is always important in Physics that you know certain things. First of all, you should know what you are looking for. Are you searching for time? Are you searching for distance? This time, you are searching for acceleration with regards to the given net force.

Now that you know what you are looking for, you need to consider the different formulas that you can use. It can be confusing to search for the right one. One formula is composed of final velocity minus initial velocity over change in time. Another possible formula is final velocity2 minus initial velocity 2 over 2(displacement.) The moment that you know what to use, it will not be too hard to do anymore.