Summary Grade 12 Physical Sciences_Projectile Motion

Projectile motion

1.1 Projectile:
 An object in free fall.
 Movement of an object in an up or down motion.



1.2 Free Fall
 The motion of an object in which the only force acting on it is gravity.
 Gravity is equal to the weight of the object.

Fg=m×g
o Fg= gravitational force
o m=mass of object
o g=gravitational acceleration (9,8 m.s-2)



1.3 Equations of motion
vf=vi+a t v2f=v2i+2a y y=vi t+1/2a t y=(vi+vf/2) t




 If an object falls from rest the initial velocity is equal to zero, therefore the equations can be
simplified to:


v=a t y=1/2a t



1.4 Vertical projectile scenarios
1. An object that is dropped or falls from a certain height
 v=0 m.s-1
 Velocity increases as object falls.
 Maximum final velocity is reached as the object hits the ground.
 The height that the object falls from is equal to its downward displacement.
 The object accelerates at 9,8 m.s-2 towards the ground.



2. An object that is projected upwards and falls back to its original position
 v is not equal to zero.