The masses of 10 kg and 20 kg, respectively, are connected by a light spring as shown in the figure. A force of 200 N acts upon the 20 kg mass. At the instant shown, the 10 kg mass the acceleration of `12m//s^(2)`. The acceleration of 20 kg mass is

Options

A. (a)12 m/`sec^(2)`
B. (b)4 m/ `sec^(2)`
C. (c)10 m/ `sec^(2)`
D. (d)zero

Answer

B

Explanation

`F_(s) = 10 (12) = 120 N`
`a_(20 kg) = (200 - 120)/(20) = 4 m//s^(2)` rightwards