Question

A man goes $100m$ North then $100m$ East and then $20m$ North and then $100\sqrt{2}m$ South West. Find the displacement.

• A. $20m$ West
• B. $20m$ East
• C. $20m$ North
• D. $20m$ South

Answer 1

The correct option is C $20m$ North

If we consider the direction of the man in the direction of x-co-ordiante, y co-ordinate and z-co-ordinate as $\hat{i},\hat{j},\hat{k}$ respectively.
Displacement: $\overrightarrow{d}=100\hat{j}+100\hat{i}+20\hat{j}+(-100\hat{i}-100\hat{j})=20\hat{j}$
($\because$ the man goes $100m$ North then $100m$ East and then $20m$ North and then $100\sqrt{2}m$ South West).