Question

If a body covers one-third of its total distance with speed v1 and remaining distance with speed v2.Then what will be its average speed.

Answer 1

LET THE TOTAL DISTANCE BE 3S

WKT AVERAGE VELOCITY =TOTALDISTANCE /TOTAL TIME

LET THE VELOCITY OF THE OBJECT WHILE IT IS COVERING ONE THIRD OF THE DISTANCE BE V1 SIMILARLY IN 2 THIRD BE V2

TOTAL TIME = T1+T2

T1=S/V1                 T2=2S/V2

AVERAGE SPEED = 3S/S/V1+2S/V2  [3S WHOLE DIVIDED BY]

                              =3S/S[1/V1+2/V2]

                              =3[V1][V2]/[V2- 2V1]