Measured over very short
distances or time intervals
Light Gate Experiment
Instantaneous Speed =
length of card / time light
beam is broken
Average Speed
Measured over
longer distances or
time intevals
Newton's Laws of Motion
Newton's 1st Law of Motion
An object will remain at rest or at a constant
speed in the same direction unless acted upon by
an external unbalanced force
Newton's 2nd Law of Motion
Force = mass x acceleration
F=ma
Newton's 3rd Law of Motion
For every action there is
an equal and opposite
reaction
If A exerts a force on B, then B exerts an
equal and opposite force on A.
Projectiles
Projectile motion is viewed as two separate motions
Horizontal
The projectile remains at a constant
speed horizontally. Excluding air
resistance, there are no forces acting
upon the projectile.
Vertical
The projectile accelerates downwards
at 9.8 m/s^2 due to weight (the force
due to gravity)
The projectile follows a curved path because it is
travelling at a constant speed horizontally, but
accelerating vertically downwards at the same time.