A net force is the remaining force that produces any acceleration of an object when all opposing forces have been canceled out. Opposing forces decrease the effect of acceleration, lowering the net force of acceleration acting on an object.
In nature, every force is opposed by other forces, such as friction or opposing gravitational forces. Forces can produce acceleration only if they are greater than the total opposing forces. If a force pushes an object but is matched by friction, the object does not accelerate. Likewise, if a force pushes against gravity but is less than the gravitational force on an object, it does not accelerate. For example, if a 15-Newton push on an object is opposed by a 10-Newton friction force, the object accelerates as if pushed by a 5-Newton net force without friction.