Question

which example provides a complete scientific description of an object in motion?
the marble changed position quickly.
the marble moved 30 cm north in 6 seconds.
the ball rolled 20 cm in 5 seconds.
the car traveled north.

Explanation:

To describe an object in motion scientifically, we need details about displacement (magnitude and direction) and time.

• "The marble changed position quickly" has no specific magnitude, direction or time - incomplete.
• "The marble moved 30 cm north in 6 seconds" has displacement (30 cm north) and time (6 seconds) - complete.
• "The ball rolled 20 cm in 5 seconds" has no direction - incomplete.
• "The car traveled north" has no magnitude or time - incomplete.

Answer:

The marble moved 30 cm north in 6 seconds.