What measures gravity?
the speed at which a mass falls. All masses fall at the same speed and all masses can fall because of gravity. gravity is measured in metres per second. Gravity on earth is 9.81m/s. This means that if you let something drop from a building it will travel 9.81 metres in 1 second. It accelerates also due to gravity so it will be greater than 19.16 after 2 seconds. Thats why they say that if you let a penny drop from the empire state building and it hit someone walking past it would kill them. This is because by the time it would have reached the person it would have gathered high acceleration and therefore would hit the person with a high force.
