Either one of the following observations tells you that an object is accelerating:
-- Three points in the object's path are not in a straight line.
-- The distance the object travels in a period of time is not the same as the
distance it travels in another period of the same duration.
it does not accelerate
If a force is being applied to a moving object, it will change its velocity (it will accelerate) appropriately.
Any force.
by adding more force
An object accelerates when all the forces acting on it don't add up to zero.
An unbalanced force will always make an object accelerate. If the object is at rest, it will start moving.
An unbalanced force will always make an object accelerate. If the object is at rest, it will start moving.
The object is accelerated in the direction of the net (or resultant) force.
Not all moving objects accelerate. In general, an object will accelerate if there is a net force acting on it. For a ball in the air, this might be gravitation + air resistance; for a moving car (once you turn the engine off) it might be the force of friction; etc.
If forces on an object are unbalanced, the object will accelerate or decelerate. If forces on an object are balanced, the object will stay still or keep moving with the same velocity.
If forces on an object are unbalanced, the object will accelerate or decelerate. If forces on an object are balanced, the object will stay still or keep moving with the same velocity.
It will not accelerate. That means that its velocity won't change.