Ashark travels with an average velocity of 12 m/s s. how long (time) would it take the shark to swim 42 m at that velocity

3.5 s

Explanation:

Time,

Where d is the distance covered and s is the speed.

Substituting 42 m for distance and 12 m/s for speed then

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.