Question

a particle travels half distance of a straight journey with speed 6m/s. the remaining part of the distance is covered with speed 2m/s for half of the remaining journey band with speed 4m/s for the other half of time. the average speed of particle is

Answer 1

lets consider it has total distance of x kilometres

So for 0.5x distance its speed was 6m /s
t1 = 1/2 x/ 6 = x/ 12

for 0.25x speed is 2m/s

t2 = 1/4x / 2 = x/ 8

and for 0.25 speed is 4m/s

t3 = 1 / 4 x / 4 = x/16

avrage speed = total distance / total time taken

= x / ( x/12 + x/8 + x/16)
= x/ ( 4x+ 6x+ 3x)/ 48
= 48x / 13 x
= 3.8 m/ s