In the absence of air resistance, all objects fall with the same acceleration
This is called the acceleration of freefall (this is also sometimes called acceleration due to gravity)
This means that for every second an object falls, its velocity will increase by 9.8 m/s
The symbol g also stands for the gravitational field strength, and can be used to calculate the weight of an object using its mass:
weight = mass × gravitational field strength
W = mg
Falling Objects without Air Resistance
In the absence of air resistance, all objects falling in a uniform gravitational field, fall with the same acceleration, regardless of their mass
So long as air resistance remains insignificant, the speed of a falling object will increase at a steady rate, getting larger the longer it falls for.
In the absence of air resistance objects fall with constant acceleration
Falling Objects with Air Resistance
Objects falling through fluids (fluids are liquids or gases) in a uniform gravitational field, experience two forces:
Weight (due to gravity)
Friction (such as air resistance)
A skydiver jumping from a plane will experience:
A downward acting force of weight (mass × acceleration of freefall)
An upward acting force of air resistance (frictional forces always oppose the direction of motion)
The force of air resistance increases with speed. This is illustrated in the image below:
