PHYSICS LECTURES

Projectile Motion

It is a two-dimensional kinematics. We consider here both the vertical and horizontal components of moving object. The figure below shows an example of projectile motion.

A projectile motion of object with initial velocity and angle of flight as given.

From the figure above, the velocity v has components v sin θ and  v cos θ. Point P(x,y) is the maximum point in the motion of the projectile. The path or curve the projectile makes is known as the parabolic path or trajectory. The motion will be analyzed using the two components separately. Things to remember in analyzing the motion:

                (1) the horizontal component of the velocity of object at every point in the trajectory is always   constant; 

                (2) the vertical component of the velocity of object is decreasing if the object's motion is going up, while increasing if going down; 

                (3) if the vertical component of the velocity of object is equal to zero, then the object is at the maximum of the trajectory;

                (4) the time the object takes to goes up to the maximum point is equal to the time it takes to goes down the ground;

                (5) we use "-g" if the object is going up and "+g" if going down.

The figure show the analysis of projectile motion.

The formula that is usually used in solving projectile motion problems.