PROJECTILE'S TRAJECTORY

Characteristics of a Projectile'sTrajectory

The force acting is only gravity.

Two components of the projectile's motion - horizontal and vertical motion.

Horizontally Launched Projectiles
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

 

Forces	Horizontal Motion No	Vertical  Motion Yes The force of gravity acts downward
Acceleration	No	Yes "g" is downward at 9.8 m/s/s
Velocity	Constant	Changing (by 9.8 m/s each second)

 

Non-Horizontally Launched Projectiles