Question

A body 'A' starts from rest with an acceleration a₁. After 2 seconds, another body 'B' starts from rest with an acceleration $a_2$. If they travel equal distances in the $5^{th}$ second after the start of A, then the ratio $a_1:a_2$ is equal to

• A. 5: 9
• B. 5: 7
• C. 9: 5
• D. 9: 7

Answer 1

The correct option is A

5: 9

$S_{nth}=u+\frac{a}{2}(2n-1)ForbodyA:n=5,a=a_{1}ForbodyB:n=3,a=a_2{u}_A=u_B=0S_{5thA}=A_{3rdB}\frac{a_1}{2}(2\times 5-1)=\frac{a_2}{2}(2\times 3-1)\Rightarrow \frac{a_1}{a_2}=\frac{5}{9}$