A) 5 : 9
B) 5 : 7
C) 9 : 5
D) 9 : 7
Correct Answer: A
Solution :
[a] : Time taken by body A,\[{{t}_{1}}=5s\] Acceleration of body \[A={{a}_{1}}\] Time taken by body \[B,{{t}_{2}}=5-2=3s\] Acceleration of body \[B={{a}_{2}}\] Distance covered by first body in 5th second after its start, \[{{S}_{5}}=u+\frac{{{a}_{1}}}{2}(2{{t}_{1}}-1)=0+\frac{{{q}_{1}}}{2}(2\times 5-1)=\frac{9}{2}{{a}_{1}}\] Distance covered by the second body in the 3rd second after its start, \[{{S}_{3}}=u+\frac{{{a}_{2}}}{2}(2{{t}_{2}}-1)=0+\frac{{{q}_{2}}}{2}(2\times 3-1)=\frac{5}{2}{{a}_{2}}\] Since \[{{S}_{5}}={{S}_{3}}\] \[\therefore \]\[\frac{9}{2}{{a}_{1}}=\frac{5}{2}{{a}_{2}}\]or\[{{a}_{1}}:{{a}_{2}}=5:9\]
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