VERTICAL PROJECTILE MOTION
Free Fall
Movement downwards due to the force of gravity only
Acceleration due to gravity = 9,8 m.s-2 down (always applies in
free fall)
Freely falling objects
Down +
Acceleration ≠ 0
Velocity = 0 at max height
Displacement = 0 if object returns to same height
Speed and displacement are symmetrical
Time symmetryan object will take the same time to reach its
highest point from projection as the time taken to fall back from the
highest point to point of projection
Air Resistance
Negligible at low speed
Non- conservative force (do not store energy)
Dissipative force
Depends on velocity/ speed and surface area
Terminal Velocity
The constant velocity that a freely falling object eventually reaches
when air resistance prevents further acceleration (air resistance =
gravity)
Equations of Motion
Vf= Vi+at
y= Vit+12at2
Vf2=Vi2+2ay
y=(Vi+ Vf2)t
Always tabulate & state sign convention
When an object is dropped from a moving “vehicle”, the Vi= the
velocity it had inside the moving “vehicle”
Displacement vs Time Graphs
Displacement is the change in position
Gradient of graph = velocity
∴
Constant velocitystraight line graph
Changing velocitycurved graph
Free Fall
Movement downwards due to the force of gravity only
Acceleration due to gravity = 9,8 m.s-2 down (always applies in
free fall)
Freely falling objects
Down +
Acceleration ≠ 0
Velocity = 0 at max height
Displacement = 0 if object returns to same height
Speed and displacement are symmetrical
Time symmetryan object will take the same time to reach its
highest point from projection as the time taken to fall back from the
highest point to point of projection
Air Resistance
Negligible at low speed
Non- conservative force (do not store energy)
Dissipative force
Depends on velocity/ speed and surface area
Terminal Velocity
The constant velocity that a freely falling object eventually reaches
when air resistance prevents further acceleration (air resistance =
gravity)
Equations of Motion
Vf= Vi+at
y= Vit+12at2
Vf2=Vi2+2ay
y=(Vi+ Vf2)t
Always tabulate & state sign convention
When an object is dropped from a moving “vehicle”, the Vi= the
velocity it had inside the moving “vehicle”
Displacement vs Time Graphs
Displacement is the change in position
Gradient of graph = velocity
∴
Constant velocitystraight line graph
Changing velocitycurved graph
