Q12 of 42 Page 31

Mass m1 moves on a slope making an angle θ with the horizontal and is attached to mass m2 by a string passing over a frictionless pulley as shown in Fig. 5.2. The co-efficient of friction between m1 and the sloping surface is μ. Which of the following statements are true?


Let’s consider a case in which normal reaction i.e.

N from figure also we know friction



Now from figure taking whole as a system then


when m1 will up and m2 will down.


Putting f in this equation


⇒


⇒ or in simply


⇒ from this option (a) is totally wrong while option (b) is correct.


Now if body m1 moves down and m2 moves up then, direction of friction force (f) becomes upward (opp. to motion).


⇒


⇒


⇒


Hence option (d) is correct but option (c) is wrong.

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