NEET Class neet Answered

Asked by akp70528438 | 28 Nov, 2021, 10:05: AM

Expert Answer

Figure shows the forces acting on blocks of masses m₁ and m₂ . Weight m₁g is acting downward. Equal reaction force R is acting upward

when the block of mass m₁ is moving , friction force μR is acting against the motion.Tension force T is acting along the string.

If we apply Newton's law to the block of mass m₁ , we get

T - μ R = T - ( μ m₁ g ) = m₁ a ...............................(1)

where a is acceleration of system.

f we apply Newton's law to the block of mass m₂ , we get

m₂ g - T = m₂ a ...............................(2)

By adding eqn.(1) and (2) , we get ,

m₂ g - ( μ m₁ g ) = ( m₁ + m₂ ) a

Hence acceleration a is given from above expression as

begin mathsize 14px style a space equals space fraction numerator open parentheses m subscript 2 space minus space mu space m subscript 1 close parentheses g over denominator left parenthesis space m subscript 1 plus space m subscript 2 right parenthesis end fraction end style

......................................(3)

We get Tension force T fromm eqn.(2) as

T = m₂ ( g - a ) .............................(4)

By substituting acceleration a from eqn.(3) , we get tension force T from eqn.94) as

begin mathsize 14px style T space equals space m subscript 2 space end subscript open parentheses g space minus space fraction numerator left parenthesis m subscript 2 subscript space end subscript space minus space mu space m subscript 1 right parenthesis space g over denominator left parenthesis m subscript 1 subscript space end subscript plus m subscript 2 subscript space end subscript right parenthesis end fraction close parentheses space space equals space fraction numerator m subscript 1 subscript space end subscript m subscript 2 over denominator m subscript 1 subscript space end subscript plus m subscript 2 end fraction space open square brackets left parenthesis 1 plus mu right parenthesis space g close square brackets end style

Answered by Thiyagarajan K | 28 Nov, 2021, 12:09: PM

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