Question

A body 'A' starts from rest with an acceleration 'a1'. After 2 s, another body 'B' starts from rest with an acceleration 'a2'. If they travel equal distances in 5th Second, after the start of A, then the ratio a1 : a2 is equal to ?A) 5 : 9B) 5 : 7C) 9 : 5D) 9 : 7

Answer 1

Distance travelled by A in 5th second

$\sf\implies\:S_A = 0 + \dfrac{a_1}{2}(2 × 5 - 1) = \dfrac {9}{2} a_1$

Distance travelled by B in 3rd second

$\sf\implies\:S_B = 0 + \dfrac {a_2}{2}(2 × 3 - 1) = \dfrac {5}{2} a_2$

As per question ;

$\sf\implies\dfrac {9}{2} a_1 = \dfrac{5}{2} a_2$

$\qquad\large {\boxed {\sf {\dfrac {a_1}{a_2} = \dfrac {5}{9}}}}$