What is this?
gravity
friction
What is this?
friction
gravity
What is this?
drop
fall
What is this?
fall
drop
What is this?
down
air resistance
What is this?
invisible
weight
What is this?
invisible
weight
What is this?
down
drop
What is this?
friction
gravity
What is this?
gravity
friction
What is this?
drop
fall
What is this?
drop
fall
What is this?
air resistance
down
What is this?
invisible
weight
What is this?
weight
invisible
What is this?
down
drop
