6. A train starts from rest from a station with
acceleration 0.2 m/s2 on a straight track and then
comes to rest after attaining maximum speed on
another station due to retardation 0.4 m/s2. If total
time spent is half an hour, then distance between
two stations is [Neglect length of train]
in (1) 216 km
(2) 512 km
(3) 728 km
(4) 1296 km
Answers
Answered by
0
Explanation:
Given,
Velocity v
1
achieve in time t
1
,due to acceleration, a
1
=0.2ms
−2
v
1
=u
1
+at
1
⇒v
1
=0+0.2t
1
Velocity reduce to zero in time t
2
, due to retardation, a
2
=−0.4ms
−2
v
2
=v
1
+at
2
⇒0=v
1
−0.4t
2
Add time
t
1
+t
2
=
0.2
v
1
+
0.4
v
1
⇒30×60=v
1
×7.5
⇒v
1
=240m/s
Apply kinematic equation
v
2
−u
2
=2as
s=
2a
v
2
−u
2
Total distance S
1
+S
2
=
2a
1
v
1
2
+
2a
2
v
1
2
=
2×0.2
240
2
+
2×0.4
240
2
=216km
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