A) 4.25 s
B) 5.25 s
C) 6.25 s
D) 7.25 s
Correct Answer: C
Solution :
Initial relative velocity of the express trainw.r.t. the passenger train, \[{{u}_{ep}}={{u}_{e}}-{{u}_{p}}=30-5=25m{{s}^{-1}}\] Final relative velocity of the express train w.r.t.the passenger train, \[{{v}_{ep}}=0\] (because express train comes to rest) From first equation of motion \[{{v}_{ep}}={{u}_{ep}}-at\] or \[0=25-4t\] or \[4t=25\] or \[t=6.25\,s\]You need to login to perform this action.
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