The masses of `10kig` and `20kg` respectively are connected by a massless spring as shown in figure. A force of `200N` acts on the `20kg` mass. At the instant shown, the `10kg` mass has acceleration `12m//sec^(2)` . What is the acceleration of `20kg` mass?

Options

A. Zero
B. `10 m//s^(2)`
C. `4 m//s^(2)`
D. `12 m//s^(2)`

Answer

C

Explanation

Let spring force is `f_(s)`

`f_(s)=10xx12=12N" "200-fs=20a`
`200-120=20a`
`a=4m//s^(2)`