Question

A particle moves 3 m north, then 4 m east and finally 6 m south. What is the distance travelled and the displacement of the particle?

• A. The displacement is 13 m.
• B. The distance travelled is 13 m.
• C. The distance travelled is 12 m.
• D. The displacement is 5 m.

Answer 1

Answer: (B), (D)

The displacement is 5 m.

Let the particle start from A and finally reach B as shown. Distance is the length of the actual path taken by it.
In this case,
distance = 3 m + 4 m + 6 m = 13 m
Displacement is the shortest distance between the initial and final position.
Here, displacement = AB
Using Pythagoras theorem,
AB $=\sqrt{(B{C}^2+A{C}^2)}$
$=\sqrt{(3^2+4^2)}m=5m$.