JEE Mains · Physics · STD 11 - 4.2 friction
A block of mass \(40 \,kg\) slides over a surface, when a mass of \(4 \,kg\) is suspended through an inextensible massless string passing over frictionless pulley as shown below. The coefficient of kinetic friction between the surface and block is \(0.02\). The acceleration of block is ............ \(ms ^{-2}\) (Given \(g =10 \,ms ^{-2}\).)
- A \(1\)
- B \(1 / 5\)
- C \(4 / 5\)
- D \(8 / 11\)
Answer & Solution
Correct Answer
(D) \(8 / 11\)
Step-by-step Solution
Detailed explanation
For \(4 \,kg\) block \(4 g - T =4 a\) For \(40 \,kg\) block \(T -40 g \times 0.02=40 a\) Adding both eq. \(40-8=44 a\) \(a =\frac{32}{44}=\frac{8}{11} \,m / s ^{2}\)
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