Characteristics of a Projectile'sTrajectory
The force acting is
Two components of the projectile's motion - horizontal and vertical motion.
Consider a cannonball projected
horizontally by a cannon from the top of a very high cliff
In the absence of gravity, the cannonball would continue its horizontal motion at a constant velocity. This is consistent with the law of inertia.
If merely dropped from rest in the presence of gravity, the cannonball would accelerate downward, gaining speed at a rate of 9.8 m/s every second. This is consistent with our conception of free-falling objects accelerating at a rate known as the acceleration of gravity.
Cannonball is projected horizontally in the presence of gravity, it would maintain the same horizontal motion as before - a constant horizontal velocity.
The force of gravity will act upon the cannonball to cause the same vertical motion as before - a downward acceleration. The cannonball falls the same amount of distance as it did when it was merely dropped from rest
The force of gravity acts downward
|No||Yes "g" is downward at 9.8 m/s/s|
|Constant||Changing (by 9.8 m/s each second)|