Objects falling through a fluid eventually reach
terminal velocity, when the resultant force acting on
them is zero and they are moving at a steady speed
Weight is a force exerted on an object
because of a gravitational force
Falling objects
Forces affecting an object falling
The weight of the object. This is a force
acting downwards, caused by the object’s
mass the Earth's gravitational field
Air resistance. This is a frictional force acting in
the opposite direction to the movement of the
object
3 stages of falling
1. At the start, the object accelerates downwards
because of its weight. There is no air resistance.
There is a resultant force acting downwards
2. As it gains speed, the object's weight stays the
same, but the air resistance on it increases. There
is a resultant force acting downwards
3. Eventually, the object's weight is balanced by
the air resistance. There is no resultant force and
the object reaches a steady speed, called the
terminal velocity
W = m x g
W = the weight, measured in newtons (N)
m = the mass, measured in kilograms (kg)
g = gravitational field strength, measured
in newtons per kilograms (N/kg)