"Might" is not the correct word. The acceleration will be reduced. Newton's third law of motion says it has to be reduced.
I think that you'll find that he's talking noticeable change. For instance, if the Earth hit an a small Asteroid head on, do you think that those of us that survived its effects would have to change the length of a year?
At the instant of collision, the velocity will change. It has to. If an object is moving in one direction, and it encounters a force in the opposite direction of its motion - even for an instant, it's velocity will change. In fact, its velocity will be less than it was before the impact, if the force is in the opposite direction. Newton's third law of motion says this has to be true.
If the object is in a state of constant velocity this is true, but what happens in the case of an object that is accelerating and thus had its velocity changing over time already?
The definition of acceleration is change in velocity with respect to time. If the velocity changes, even for an instant, then the acceleration must also change, even if it's just for an instant.
This is true, but by how much must it change?
The collision does alter the acceleration. The collision provides a force in the opposite direction of travel. A force in the opposite direction of travel will reduce the velocity of the falling object, even if it's just for an instant. If the velocity of an object is reduced with respect to time, then the object is said to decelerate.
Here is where you go wrong. Remember that a falling object is accelerating at 9.8 m/s
2. Lets go back to our Skydiver. On jumping out of the plane the Skydiver will immediately begin experiencing Air Resistance, thus a force in the opposite direction of travel.
Will the Skydiver accelerate, or decelerate?
If you say Accelerate, then explain how this is true if the hilited part above is correct, and if you say decelerate, then explain how come when they jump out of the plane they don't just float in the air and their downward velocity decreases due to deceleration.
Incorrect
Let me break this down concept by concept.
1. If an object is in motion it has a velocity. Velocity is the speed of the motion and direction of motion.
2. Acceleration is a change in velocity with respect to time.
3. If the velocity is increasing with respect to time it is said to accelerate.
4. If the velocity is decreasing with respect to time it is said to decelerate.
Let me summarize this.
If velocity increases with respect to time there is acceleration.
If the velocity stays constant with respect to time there is no acceleration.
If the velocity decreases with respect to time there is deceleration.
Are any of the above statements incorrect? No.
So far so good, the mistake is coming up
This is wrong because in your example an object is accelerating downwards. To be perfectly clear, this means that the velocity is increasing in the downwards direction with respect to time. In your example the accelerating object then collides with another object.
And here is your mistake, you make an incorrect assumption that all collisions will cause an accelerating object to decelerate. You are missing two scenarios that I showed you with Air Resistance. The collision may simply lessen the Acceleration id the force is less than that of gravity, or it might reduce it to zero if it is equal to gravity. It will only cause a deceleration if the force experienced is greater then the force applied by gravity.
This is wrong. Newton's third law says that for every action there is an equal and opposite reaction. If your example object is accelerating downwards, at the instant of impact with the other object the velocity will change. It has to, because it is encountering a force in the opposite direction of travel. The opposite force causes the velocity to decrease. What term do we use when the velocity of an object decreases with respect to time? The term is deceleration.
You are still forgetting that your falling object is already accelerating. You keep treating it as if it's travelling at a constant velocity, not like it accelerating.
If you are in a 1,544 kg Ferrari 488 Spider and are accelerating at along a runway at 25m/s
2 and hit a stationary 2 gram bee, will that cause the car to decelerate?
If there is deceleration, and Newton has have proven there is, your statement is wrong.
Again, remember that you're dealing with an already accelerating object, not one at constant Velocity, it really makes a difference.
If you want to be taken seriously, admit you were wrong and move on.
Good advice, I suggest you take it on this one too.