Laws of Motion

JEE Main level, single correct, medium

179 of 210

Question 179 of 210

Two masses m1=5kg{m}_{1}=5kg and m2=10kg{m}_{2}=10kg, connected by an inextensible string over a frictionless pulley, are moving as shown in the figure. The coefficient of friction of horizontal surface is 0.150.15. The minimum weight m that should be put on top of m2{m}_{2} to stop the motion is:

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Answer: (C) 27.3kg27.3kg

T=5gT=5g⇒μ(10+m)≥5g\Rightarrow \mu \left(10+m\right)\geq 5g⇒10+m≥50.15\Rightarrow 10+m\geq \dfrac{5}{0.15}
⇒m≥23.33kg\Rightarrow m\geq 23.33kg⇒m=27.3kg\Rightarrow m=27.3kg.

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