Final answer:
An object subjected to two equal and opposite forces of 5N in the horizontal direction cannot be accelerating, since the net horizontal force would be zero according to Newton's first law, which leads to no change in motion.
Step-by-step explanation:
If two forces of 5N act on the opposite horizontal sides of an object, the object can be at various states of motion depending on the resultant net force. Let's examine each scenario outlined in the question, applying the principles of Newton's first law to determine the object's motion.
- The object can be at rest if the two forces cancel each other out, resulting in no net force and consequently no acceleration, as per Newton's first law, which states that an object at rest will remain at rest if the net force is zero.
- The object can move with a constant speed to the right provided there is no net force acting in the horizontal direction (ignoring any vertical forces such as gravity or normal force). This would mean that both 5N forces are balanced, and the object continues with its current state of motion, whether at rest or moving.
- The object can also move at constant speed upward as this motion is not in the horizontal direction where the two forces are acting. As long as there are other forces providing upward motion and these forces are balanced, constant speed in the vertical direction is possible.
- However, the object cannot be accelerating horizontally if we assume that these are the only two forces acting on it. If the net horizontal force is zero (5N to the left and 5N to the right), then by Newton's second law (Fnet = ma), there is no acceleration.
Therefore, the correct answer to this physics problem is that the object cannot be accelerating if both 5N forces are the only forces acting upon it and are in the horizontal direction.