A person walks a distance of 40m towards west with a speed of 2m/s and 20m towards north with a speed of  4m/s. Then the average velocity for his journey.

Displacement along west  S1=40 mTime taken  t1=402=20SDisplacement along north  S2=20 mTime taken  t2=204=5S∴ Displacement Vector  S¯=40i^+20j^∴ Total displacement  S=S12+S22                                 =402+202=1600+400=2000=205∴ Average velocity = Total displacement  Total time                                   =20520+5=20525=455=45=42.24=1.78m/s