What is the difference between accurate data and reproducible data?

Accuracy is a general concept while precision is more of a mathematical concept. On the whole though, the conceptual boundary between the use of the two words is kind of fuzzy. While accuracy means being correct and true in every detail, precision means being more exact and to the point in reference to a certain standard or method. For example, you can be accurate with your answer but you can be precise with the method of calculation.

Accuracy may also refer to the truthfulness of data and records. For example, you can have accurate demographic data of the people in a city. But, in this case precise would refer more to the inferences you have drawn from the accurate date in your possession about the demography of the city in question.

Both accuracy and precision can also refer to results obtained from mechanical objects like a compass and watch. For example, if you have tuned or set your watch and compass accurately, it will be able to give you the current time and direction at any given moment with precision.

the bal will not change its velocity.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.