Two blocks of mass $$4$$ kg and $$2$$ kg are connected by a heavy string and placed on rough horizontal plane. The $$2$$ kg block is pulled with a constant force F. The coefficient of friction between the blocks and the ground is $$0.5$$. What is the value of F so that tension in the string is constant throughout during the motion of the blocks ? (g$$ $$=$$ $$10$$ $$m/s2)

Question

Infinity Learn · Accepted Answer

Consider a segment AB of the string and tension at its ends are T₁ and T₂as shown. If 'a' be the acceleration of the string, then T₁ - T₂= m x a. When a = 0, T₁ = T₂. To make the tension constant, the net force on the system must be zero.
$∴$ F - µm₁g - µm₂g = 0 ⇒ F = µ(m₁ + m₂)g
= 0.5 x 6 x 10 N = 30 N

Different types of Forces

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