A) \[750\,m\]
B) \[1000\,m\]
C) \[1250\,m\]
D) \[2250\,m\]
Correct Answer: C
Solution :
For train A, \[{{u}_{A}}=72km/h=72\times \frac{5}{18}m/s=20m/s\] For train B, \[{{u}_{B}}=72km/h=72\times \frac{5}{18}m/s=20m/s\] \[\therefore \,\,{{u}_{BA}}={{u}_{B}}-{{u}_{A}}=20m/s-20m/s=0m/s\] \[{{a}_{BA}}={{a}_{B}}-{{a}_{A}}=1m/{{s}^{2}}-0m/{{s}^{2}}=1m/{{s}^{2}}\] \[t=50s\] \[{{S}_{BA}}={{u}_{BA}}t+\frac{1}{2}{{a}_{BA}}{{t}^{2}}=0\times 60+\frac{1}{2}\times 1\times {{\left( 50 \right)}^{2}}=1250m.\]
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