Dave owns a construction business and is in the process of buying a laptop. He is looking for a laptop with a hard drive that will likely continue to function if the computer is dropped. Which type of hard drive does he need?

only #2 represents an object at rest on a table.

in #1, there is no normal force due to the table; the object is accelerating downward.

in #3, the vertical forces are not balanced; the object is accelerating downward.

in #4, neither the vertical nor the horizontal forces are balanced. the object is accelerating upwards and to the right.