What if net force is zero

Other examples include:. Newton's First Law can also be used to explain the movement of objects travelling with non-uniform motion. This includes situations when the speed, the direction, or both change. For example, when a car accelerates, the driving force from the engine is greater than the resistive forces.

The resultant force is not zero. The submarine above has both vertical forces and horizontal forces acting on it. The horizontal forces will not affect its vertical movement and the vertical forces will not affect its horizontal movement.

The horizontal forces are equal in size and opposite in direction. Therefore, the velocity is not changing. If the object was already moving, then it will just keep moving. So, yes, the object can be moving when there is no force applied to it.

Note: "force" in this discussion is to be interpreted as net force. Net force is the vector sum of all forces acting on the object. Newton's First Law of Motion: I. Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.

Newton's Laws of Motion. Misconceptions Forces and Motion Many students think that a force is needed to keep an object moving with a constant speed Number of Resources 3 Number of References 12 Number of Diagnostic Resources 2. Forces and Motion Most students think that if an object is moving, there must be a force in the direction of its motion Number of Resources 1 Number of References 10 Number of Diagnostic Resources 0.

Newton's First Law formalises Inertia. We've won an award! Learn more. Close Physics Links Explorer Explore the links between different physics concepts.