Question

Which of the following statements about distance is true?

• A. It cannot be negative
• B. It cannot be zero
• C. It can never be lesser than magnitude of displacement
• D. It can never decrease with time

Answer 1

The correct option is D

It can never decrease with time

Explanation of correct option

Option C,

1. Distance is the total path traveled by the object.
2. It is the path length covered by the object.
3. Displacement is the change in the position of an object. It has magnitude and direction.
4. Distance is always greater than or equal to displacement.

Example

1. In the figure, the boy goes to the house, and then to the tree.
2. So the distance traveled will be AB+BC.
3. The displacement of the boy, i.e., the shortest distance from the initial and final position of the boy is AC.

Distance is always greater than or equal to displacement.

So it can be never lesser than the magnitude of displacement.

Option C is correct.

Option D,

1. It is the path length of an object traveling.
2. When an object moves at a certain time, the distance increases, it never decreases with time. The longer an object moves, irrespective of the direction, the distance increases. So, it cannot decrease with time.

Option D is correct.

Explanation of incorrect options

Options A and B,

1. Since it is the path length, it cannot be negative or zero; it is always positive.

Options A and B are incorrect

Therefore, Option C and D are correct.