Question

which situation is contrary to newtons first law of motion? an object at rest stays at rest as long as unbalanced forces act on it. an object at rest begins to move when an external force is applied. a moving object slows down when an external force is applied. a moving object has a constant velocity under the influence of balanced forces.

Explanation:

Newton's first law of motion states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. An object having a constant velocity under the influence of balanced forces (net - force is zero) is in accordance with this law as there is no unbalanced force to change its state of motion. An object at rest staying at rest as long as unbalanced forces act on it has incorrect wording (it should be as long as no unbalanced forces act on it). An object at rest beginning to move when an external force is applied and a moving object slowing down when an external force is applied are more related to Newton's second law which relates force, mass and acceleration.

Answer:

A moving object has a constant velocity under the influence of balanced forces.