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 10 kg block is

Options

A. `3.2 m//s^2`
B. `2.0 m//s^2`
C. `1.6 m//s^2`
D. `0.8 m//s^2`

Answer

B

Explanation

Let us check upto what value of F, both block move together.

10 kg block will not slip over the 15 kg bolck become maximum as it is created only by frictional force exerted by 10 kg block on it.
`a_1 > a_"2(max)"`
`F=100N" ":. "for" F=80N,"both will move togrther"`
`F=25 a," "a=80/25=3.2m//s^2`