(a) Apply Newton's first law to each of the following situations. In which situations can you conclude that the object is undergoing a net interaction with one or more other objects? (1) A book slides across the table and comes to a stop. (2) A proton in a particle accelerator moves faster and faster. (3) A car travels at constant speed around a circular race track. (4) A spacecraft travels at a constant speed toward a distant star. (5) A hydrogen atom remains at rest in outer space. (b) A spaceship far from all other objects uses its rockets to attain a speed of. The crew then shuts off the power. According to Newton's first law, which of the following statements about the motion of the spaceship after the power is shut off are correct? (Choose all statements that are correct.) (1) The spaceship will move in a straight line. (2) The spaceship will travel on a curving path. (3) The spaceship will enter a circular orbit. (4) The speed of the spaceship will not change. (5) The spaceship will gradually slow down. (6) The spaceship will stop suddenly.

Newton’s first law states that everybody persists in its state of rest or of traveling with a constant (invariant) speed in a constant direction, except to the extent that it is forced to vary that state by all forces acting on it.

(1) A book sliding across the table will continue to slide until and unless an external type of force is applied to it, which is friction, as friction acts on the book by the table; therefore, the book comes to a stop.

(2) A proton is a particle accelerator that will not accelerate by itself. It will need an external force to accelerate it.

(3) A car will continue to drive at a constant speed without an external, but here, the car is moving in a circular race track, so some force must be acting on the car to draw it towards the center of the circle.

(4) The spacecraft is moving at a constant speed, i.e., it is neither speeding up nor slowing down; therefore, there is no external force.

(5) The Hydrogen atom is at rest, and since nothing is moving, there is no external force.

Therefore, you can conclude that situations (1), (2), (3) are undergoing interaction with one or more objects.

The spaceship is moving with speed of , and it will continue to do the same so until and unless any other force is applied to it, and here, in this case, no external force is applied. So, you can say that the spaceship will continue to move in a straight line without changing its speed.

Also, there is no description of a spaceship's circular motion or slowing down or stoppage. So, options (2), (3), and (5) are not correct.

Therefore, statements (1) and (4) are the correct statements.