Question

a train covers half of its journey with a speed of 30 m/s and other half with a speed of 40 m/s calculate the average speed of the train during whole journey​

Answer 1

hi friend

Answer:

Average speed=total distance/total time

d=distance travelled at 30m/s and distance travelled at 40m/s … same distance

time=distance/speed

time at 30m/s =d/30

time at 40 m/s=d/40

total time=d/30 + d/40= 7d/120

average speed= (d+d)/(7d/120)= 240/7=34.2857 m/s

It is not the average of the speeds because he spends more time at 30 m/s then at 40 m/s

hope it helps you

mark this as braniliest

Answer 2

S = total distance.

T1 and T2 are durations for covering half total distance.

S/2 = 30 x T1

S/2 = 40 x T2

total time T = T1 + T2 = S x (1/60 + 1/80)

Average velocity, V = S/(T1 + T2)= 240/7 m/s = 34.28 m/s