Correct Answer - B
Here, `m_1=20 kg, m_2= 5 kg` , Force = 40 N
`therefore a_1=2 m s^(-2) and a_2=8 m s^(-2)`
`1/2m_1(a_1t_A)^2=1/2m_2(a_2t_B)^2`
`therefore 20 xx 4 xxt_A^2 = 5 xx 64 xx t_B^2`
`therefore t_A^2/t_B^2 =(5xx64)/(20xx4)=4/1 "" or "" t_A/t_B=2`