A cannonball with a mass of 50 kilograms and a golf ball with a mass of 0. 8 kilograms are dropped in a vacuum from a height of 10 meters. Compare the acceleration of each object as they fall.

It's gonna take a huge amount of time and effort, and we're gonna spend a huge amount of money, to build a vacuum chamber big enough to do this experiment.  

So when we're finally ready to try it, the cannonball and golf ball will make a  kind of cute experiment, but let's make it really interesting.  Let's ALSO try it with a feather, an apple, a watermelon, a tennis ball, a basketball, a coffeepot, a chair, an old computer, a set of dishes, a trombone, a bicycle, a math book, a TV set, a gallon of milk, a skateboard, a shotgun, a concrete block, a car, a waterbed, a schoolbus, a battleship, your dog, and my wife !

Drop every single one of them from a height of 10 meters.

Every single one of them accelerates at 9.8 m/s² as it falls, takes 1.429 seconds to reach the floor, and hits the floor at a speed of 14 m/s.  The feather, the schoolbus, and my wife stay together all the way down.

The only way this doesn't happen is if ...

-- you do this experiment in some other place that's not Earth, or

-- you throw one of the objects and you don't just drop it, or

-- the vacuum chamber has a leak and some air gets into it.

Because that's how gravity works.

a. is the answer because they are not shared

scientific laws are the result of testing theories and proving them to be facts.