What is Distance & Displacement ?
Distance vs Displacement
Distance (āĻĻā§ā§°āϤā§āĻŦ): Distance means the total path travelled by an object. (āĻĻā§ā§°āϤā§āĻŦ āĻŽāĻžāύ⧠āĻā§āύ⧠āĻŦāϏā§āϤā§āϝāĻŧā§ āĻ āϤāĻŋāĻā§ā§°āĻŽ āĻā§°āĻž āĻŽā§āĻ āĻĒāĻĨāĨ¤)
Formul / āϏā§āϤā§ā§°: Distance = Total path travelled (āĻĻā§ā§°āϤā§āĻŦ = āĻ āϤāĻŋāĻā§ā§°āĻŽ āĻā§°āĻž āĻŽā§āĻ āĻĒāĻĨ)
Example / āĻāĻĻāĻžāĻšā§°āĻŖ: Distance: A person walks 3 m east and then 4 m north. (āĻāĻāύ āĻŦā§āϝāĻā§āϤāĻŋāϝāĻŧā§ 3 m āĻĒā§āĻŦāϞ⧠āĻā§°ā§ āϤāĻžā§° āĻĒāĻŋāĻāϤ 4 m āĻāϤā§āϤ⧰āϞ⧠āĻ’āϞāĨ¤)
Path Covered: First path (A) = 3 m, Second path (B) = 4 m
Formula: Distance = Total path travelled (āĻĻā§ā§°āϤā§āĻŦ = āĻ āϤāĻŋāĻā§ā§°āĻŽ āĻā§°āĻž āĻŽā§āĻ āĻĒāĻĨ)
Distance = 3 m + 4 m = 7 m, Ans: 7 m
The total path covered was 7 m. (āĻŽā§āĻ āĻ āϤāĻŋāĻā§ā§°āĻŽ āĻā§°āĻž āĻĒāĻĨ āĻāĻāĻŋāϞ 7 āĻŽāĻŋāĻāĻžā§°āĨ¤)
Key Point / āĻŽā§āĻā§āϝ āĻāĻĨāĻž: i. Distance has only magnitude. (Distance āϤ āĻā§ā§ąāϞ āĻŽāĻžāύ āĻĨāĻžāĻā§āĨ¤)
ii. It is a scalar quantity. (āĻ āĻāĻāĻž Scalar quantityāĨ¤)
Displacement (āϏ⧰āĻŖ): Displacement means the shortest straight path from the starting point to the ending point. (āϏ⧰āĻŖ āĻŽāĻžāύ⧠āĻā§°āĻŽā§āĻāĻŖāĻŋ āĻŦāĻŋāύā§āĻĻā§ā§° āĻĒā§°āĻž āĻļā§āώ āĻŦāĻŋāύā§āĻĻā§āϞ⧠āϏ⧰ā§āĻŦāύāĻŋāĻŽā§āύ āϏā§āĻāĻž āĻĻā§ā§°āϤā§āĻŦāĨ¤)
Formul / āϏā§āϤā§ā§°: Displacement = Shortest straight distance between start and end point (āϏ⧰āĻŖ = āĻā§°āĻŽā§āĻāĻŖāĻŋ āĻā§°ā§ āĻļā§āώ āĻŦāĻŋāύā§āĻĻā§ā§°
āĻŽāĻžāĻā§° āϏ⧰ā§āĻŦāύāĻŋāĻŽā§āύ āϏā§āĻāĻž āĻĻā§ā§°āϤā§āĻŦ)
Example / āĻāĻĻāĻžāĻšā§°āĻŖ: A person walks 3 m east and then 4 m west. (āĻāĻāύ āĻŦā§āϝāĻā§āϤāĻŋāϝāĻŧā§ 3 m āĻĒā§āĻŦāϞ⧠āĻā§°ā§ āϤāĻžā§° āĻĒāĻŋāĻāϤ 4 m āĻĒāĻļā§āĻāĻŋāĻŽāϞ⧠āĻ’āϞāĨ¤)
Final position = 1 m west from start (āĻļā§āώ āĻ ā§ąāϏā§āĻĨāĻžāύ = āĻā§°āĻŽā§āĻāĻŖāĻŋā§° āĻĒā§°āĻž 1 m āĻĒāĻļā§āĻāĻŋāĻŽāϤ)
Displacement = 1 m west (āϏ⧰āĻŖ = 1 m āĻĒāĻļā§āĻāĻŋāĻŽ)
Key Point / āĻŽā§āĻā§āϝ āĻāĻĨāĻž: i. Displacement has magnitude and direction.(Displacement āϤ āĻŽāĻžāύ āĻā§°ā§ āĻĻāĻŋāĻļ āĻĻā§āϝāĻŧā§āĻāĻž āĻĨāĻžāĻā§āĨ¤)
ii. It is a vector quantity. (āĻ āĻāĻāĻž Vector quantityāĨ¤)
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MCQ on Distance & Displacement
- What is distance ? Distance āĻāĻŋ ?
A. Shortest path B. Total path travelled C. Speed of object D. Direction only
Ans: B. Total path travelled
Explanation: Distance is the complete path covered by an object. āĻŦā§āϝāĻžāĻā§āϝāĻž: Distance āĻŽāĻžāύ⧠āĻā§āύ⧠āĻŦāϏā§āϤā§āϝāĻŧā§ āĻ āϤāĻŋāĻā§ā§°āĻŽ āĻā§°āĻž āĻŽā§āĻ āĻĒāĻĨāĨ¤
2. What is displacement ? Displacement āĻāĻŋ ?
A. Total path travelled B. Speed of motion C. Shortest straight path from start to end D. Circular path
Ans: C. Shortest straight path from start to end
Explanation: Displacement is the shortest straight distance between initial and final position. āĻŦā§āϝāĻžāĻā§āϝāĻž: Displacement āĻŽāĻžāύ⧠āĻā§°āĻŽā§āĻāĻŖāĻŋ āĻā§°ā§ āĻļā§āώ āĻ ā§ąāϏā§āĻĨāĻžāύ⧰ āĻŽāĻžāĻā§° āϏ⧰ā§āĻŦāύāĻŋāĻŽā§āύ āϏā§āĻāĻž āĻĻā§ā§°āϤā§āĻŦāĨ¤
3. Which quantity has only magnitude ? āĻā§āύ ā§°āĻžāĻļāĻŋāϤ āĻā§ā§ąāϞ āĻŽāĻžāύ āĻĨāĻžāĻā§ ?
A. Displacement B. Velocity C. Distance D. Force
Ans: C. Distance
Explanation: Distance has magnitude only. āĻŦā§āϝāĻžāĻā§āϝāĻž: Distance āϤ āĻā§ā§ąāϞ āĻŽāĻžāύ āĻĨāĻžāĻā§āĨ¤
4. Which quantity has both magnitude and direction ? āĻā§āύ ā§°āĻžāĻļāĻŋāϤ āĻŽāĻžāύ āĻā§°ā§ āĻĻāĻŋāĻļ āĻĻā§āϝāĻŧā§āĻāĻž āĻĨāĻžāĻā§ ?
A. Distance B. Speed C. Displacement D. Mass
Ans: C. Displacement
Explanation: Displacement is a vector quantity. āĻŦā§āϝāĻžāĻā§āϝāĻž: Displacement āĻāĻāĻž vector quantityāĨ¤
5. Distance is a ______ quantity. Distance āĻāĻāĻž ______ ā§°āĻžāĻļāĻŋāĨ¤
A. vector B. scalar C. force D. directional
Ans: B. scalar
Explanation: Scalar quantities have only magnitude. āĻŦā§āϝāĻžāĻā§āϝāĻž: Scalar ā§°āĻžāĻļāĻŋāϤ āĻā§ā§ąāϞ āĻŽāĻžāύ āĻĨāĻžāĻā§āĨ¤
6. Displacement is a ______ quantity. Displacement āĻāĻāĻž ______ ā§°āĻžāĻļāĻŋāĨ¤
A. scalar B. vector C. simple D. fixed
Ans: B. vector
Explanation: Vector quantities have magnitude and direction. āĻŦā§āϝāĻžāĻā§āϝāĻž: Vector ā§°āĻžāĻļāĻŋāϤ āĻŽāĻžāύ āĻā§°ā§ āĻĻāĻŋāĻļ āĻĻā§āϝāĻŧā§āĻāĻž āĻĨāĻžāĻā§āĨ¤
7. A person walks 3 m east and then 4 m north. What is the distance ? āĻāĻāύ āĻŦā§āϝāĻā§āϤāĻŋāϝāĻŧā§ 3 m āĻĒā§āĻŦāϞ⧠āĻā§°ā§ āϤāĻžā§° āĻĒāĻŋāĻāϤ 4 m āĻāϤā§āϤ⧰āϞ⧠āĻ’āϞāĨ¤ Distance āĻāĻŋāĻŽāĻžāύ ?
A. 4 m B. 5 m C. 7 m D. 12 m
Ans: C. 7 m
Explanation: Distance = 3 m + 4 m = 7 m. āĻŦā§āϝāĻžāĻā§āϝāĻž: Distance = 3 m + 4 m = 7 māĨ¤
8. In the same example, what is the displacement ? āĻāĻā§āĻāĻž āĻāĻĻāĻžāĻšā§°āĻŖāϤ displacement āĻāĻŋāĻŽāĻžāύ ?
A. 3 m B. 4 m C. 5 m D. 7 m
Ans: C. 5 m
Explanation: Displacement is the shortest straight path: √(3² + 4²) = 5 m. āĻŦā§āϝāĻžāĻā§āϝāĻž: Displacement āĻšā§āĻā§ āϏ⧰ā§āĻŦāύāĻŋāĻŽā§āύ āϏā§āĻāĻž āĻĻā§ā§°āϤā§āĻŦ: √(3² + 4²) = 5 m
9. Which of the following can never be zero if motion occurs ? āĻāϤāĻŋ āĻš’āϞ⧠āϤāϞ⧰ āĻā§āύāĻā§ āĻā§āϤāĻŋāϝāĻŧāĻžāĻ āĻļā§āύā§āϝ āύāĻšāϝāĻŧ ?
A. Displacement B. Velocity C. Distance D. Acceleration
Ans: C. Distance
Explanation: Distance is always positive when an object moves. āĻŦā§āϝāĻžāĻā§āϝāĻž: āĻŦāϏā§āϤ⧠āĻāϤāĻŋ āĻā§°āĻŋāϞ⧠Distance āϏāĻĻāĻžāϝāĻŧ āϧāύāĻžāϤā§āĻŽāĻ āĻšāϝāĻŧāĨ¤
10. Which statement is correct ? āĻā§āύ āĻāĻā§āϤāĻŋāĻā§ āϏāĻ āĻŋāĻ ?
A. Distance can have direction B. Displacement is always greater than distance
C. Distance is always equal to or greater than displacement D. Distance is a vector quantity
Ans: C. Distance is always equal to or greater than displacement
Explanation: The total path is always greater than or equal to the shortest path. āĻŦā§āϝāĻžāĻā§āϝāĻž : āĻŽā§āĻ āĻĒāĻĨ āϏāĻĻāĻžāϝāĻŧ āϏ⧰ā§āĻŦāύāĻŋāĻŽā§āύ āϏā§āĻāĻž āĻĻā§ā§°āϤā§āĻŦāϤāĻā§ āĻŦā§āĻāĻŋ āĻŦāĻž āϏāĻŽāĻžāύ āĻšāϝāĻŧ