10. A train is moving on straight track with velocity
Vo = 13.5 ms. To stop the train at a particular station,
the driver applies brakes at t = 0, which is caused of a
retardation proportional to the velocity of the train. The
speed of train reduces 50% in the first to = 4 In(2)s. Find
velocity of train (in msl) at t= 4 s. (Given, e = 2.7)
Answers
Answer:
11th
Physics
Motion in a Straight Line
Graphs in Relative Motion
The driver of a train movin...
PHYSICS
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Asked on December 27, 2019 by
Poulomi Tehreem
The driver of a train moving with a constant speed v
1
along a straight track sights another train at a distance d ahead of him on the same track moving in the same direction with a constant speed v
2
. He at once applies the brakes and gives his train a constant retardation f. There will be a collision of the trains if:
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ANSWER
Relative velocity v
12
=v
1
−v
2
,
Relative separation s
12
=d,
Relative acceleration a
12
=a
1
−a
2
=−f
Let at time t , trains collides.
Using s=ut+
2
1
at
2
⇒d=(v
1
−v
2
)t−
2
1
ft
2
⇒ft
2
−2(v
1
−v
2
)t+2d=0,
For real solution of t, (2(v
1
−v
2
))
2
−4×f×2d>0
⇒
2f
(v
1
−v
2
)
2
>d
∴ For collision v
1
>v
2
and
2f
(v
1
−v
2
)
2
>d