1.A 2.6kg book sits rest on a flat desk. 2.A 1.9kg book sits at rest on a flat desk. A student pushes the book on to the right, but the book is held in place by static friction.

3.A 2.4kg book slides across a flat desk accelerating at .25m/s^2 to the right. A student is pushing the book on to the right, but the book is experiencing a frictional force.

4. A rocket lifts off Earth’s surface, accelerating upward at 7.4m/s^2. Its engines generate 1,300N of thrust. What is the mass of the rocket?(ignore wind resistance)