A block of mass 15 kg is place over a frictionless horizontal surface. Another block of mass 10 kg is place over it, that is connected with a light string passing over two pulleys fasted to the 15 kg block. A force F 80N is applied horizontally to the string. Friction coefficient between two blocks is 0.6. T portion of the string between 10 kg block and the upper pulley is horizontal. Pulley,string and connecting ro are massless. (Take `g=10 m//s^2`)

The magnitude of acceleration of the 15 kg block is

Options

A. `4.2 m//s^2`
B. `3.2 m//s^2`
C. `16//3 m//s^2`
D. `2.0 m//s^2`

Answer

B