![Picture](/uploads/4/7/6/5/47657887/643465753.jpg?376)
Upon observing an apple fall from a tree
Isaac Newton began thinking about how
the apple accelerated since its velocity
changes from zero as it is hanging from
the tree and moves towards the ground
therefore by his second law there must
be a force that acts on the apple to cause
this acceleration, calling it ‘gravity’ and
the associated acceleration the ‘acceleration
due to gravity’.