Two blocks A and B attached to each other by a massless spring or kept on a rough horizontal surface (`mu=0.1`) and pulled by a force of200N as shown in figure. If at some instant, the 10 kg mass has an acceleration of `12 ms^(-2)` . what is the acceleration of 20 kg mass (in `ms^(2)`).

Explanation

For A : `Kx-mu m_(A)g=m_(A)a`
`kx-0.1(10)(10)=10(12)`
For B : `200-kx-mu m_(B)g=m_(B)a`
`200-130-0.1(20)10=20a`
`a=2.5 ms^(-2)`.