Question

A $1.0 kg$ block of wood sits on top of an identical block of wood, which sits on top of a flat level table made of plastic. The coefficient of static friction between the wood surfaces is $\mu_1$, and the coefficient of static friction between the wood and plastic is $\mu_2$. A horizontal force F is applied to the top block only, and this force is increased until the top block starts to move. The bottom block will move with the top block if and only if

• A. $\mu_1<\frac{1}{2} \mu_2$
• B. $\frac{1}{2} \mu_2<\mu_1<\mu_2$
• C. $\mu_2<\mu_1$
• D. $2 \mu_2<\mu_1$

Answer 1

Answer: (D)

Correct answer is (d) $2 \mu_2<\mu_1$