Which of the following statements is not true? a. you are exposed to nuclear radiation every day. b. most of the nuclear radiation you are exposed to occurs naturally in the environment.
c. naturally occurring nuclear radiation is called background radiation.
d. all natural radiation is at a level low enough to be safe.

okay i have so many questions. but the big one here is: um wt..f is this mess? ?

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.