WBJEE · Physics · Laws of Motion
A block of mass \(m_{2}\) is placed on a horizontal table and another block of mass \(m_{1}\) is placed on top of it. An increasing horizontal force \(F=\alpha t\) is exerted on the upper block but the lower block never moves as a result. If the coefficient of friction between the blocks is \(\mu_{i}\) and that between the lower block and the table is \(\mu_{2}\), then what is the maximum possible value of \(\mu_{1} / \mu_{2} ?\)
- A \(\frac{m_{2}}{m}\)
- B \(1+\frac{m_{2}}{m_{1}}\)
- C \(\frac{m_{1}}{m_{2}}\)
- D \(1+\frac{m_{1}}{m_{2}}\)
Answer & Solution
Correct Answer
(B) \(1+\frac{m_{2}}{m_{1}}\)
Step-by-step Solution
Detailed explanation
According to the question. \(\therefore \quad N_{2}=m_{2} g+N_{1}=\left(m_{1}+m_{2}\right) g\) : Lower block never moves. \(\therefore \quad f_{r_{2}} \geq f_{n}\) \(\quad \mu_{2} N_{2} \geq \mu_{1} N_{1} \Rightarrow \mu_{2}\left(m_{1}+m_{2}\right) g \geq \mu_{1} m_{1} g\)…
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