a metro train runs from station a to b to c. it takes 4 mins in travelling from a to b. the train halts at station b for 20 s. then its starts from station b and reaches station c in next 3 mins. at the start the train accelerates for 10 sec to reach the constant speed of 72km/hr . the train moving with constant speed is brought to rest in 10 sec at the next station. plot the velocity -time graph for the train travelling from station a to b to c. calculate the distance between the stations a b and c
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Answers
Answer:
a-b = 4.6 km
b - c = 3.4 km
a-c = 8 km
Explanation:
a metro train runs from station a to b to c
Takes 4 mins in travelling from a to b
train accelerates for 10 sec to reach the constant speed of 72km/hr
brought to rest in 10 sec at the next station.
72km/hr = 72 * 1000/3600 = 20 m/s
Time to travel with constant Speed = 4*60 - 10 - 10 = 220 sec
acceleration = 20/10 = 2 m/s²
Distance Covered from a to b
= 20²/(2*2) + 20*220 + 20²/(2*2)
= 100 + 4400 + 100
= 4600 m
= 4.6 km
Distance covered from b to c
= 20²/(2*2) + 20*160 + 20²/(2*2)
= 100 + 3200 + 100
= 3400 m
= 3.4 km
a-b = 4.6 km
b - c = 3.4 km
a-c = 8 km
Answer:
a to b. 4.6
b to c 3.4
Explanation:
distance covered from a to b is
v= 72 km/hr= 20 m/s
time = 4×60=240
halt at b for 20 sec t2= 20 sec
so t1 = 240 -20 = 220 sec
s for a to b is
v × t1 + v × t2= 20 × 220 + 1/2 × 20 × 20
= 4400 + 200 = 4600 m = 4.6 km
distance covered from b to c is
v = 20 m/ s
t1 = 10 sec , t2 = 160 sec, t3= 10 sec
= 1/2 v× t1 + v× t2+1/2×v×t3
=1/2 ×20 ×10 + 20 ×160 + 1/2 × 20×10
= 100+3200+100
=3400 m=3.4 km