Question

a train starting from rest attains a maximum speed of 54 kilometre per hour in 30 seconds with uniform acceleration if then travel with the speed for 40 seconds and then brought to rest in further 30 second with uniform retardation calculate Total distance travelled​

Answer 1

The train starts from rest,

u=0

v=54km/hr

=15m/s

t=30s

a=(v-u)/t

=(15-0)/30

=1/2 m/s^2

s=ut+1/2at^2

=0*30+1/2*1/2*900

=0+225m

=225m

Continues to travel with the same speed,

speed=15m/s

time=40s

distance=speed*time

=15*40

=600m

Train brought to rest,

u=15m/s

v=0

t=30s

a=(v-u)/t

=(0-15)/30

=-15/30

=-1/2 m/s^2

s=ut+1/2at^2

=15*30+1/2*-1/2*900

=450-225

=225m

Total distance=225+600+225

=1050m

Hope it helps............

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