Q 11-04-046JEE MainTop questionHard
A $2$ kg block rests on an $8$ kg block, which lies on a smooth floor. The coefficient of static friction between the blocks is $0.3$. The maximum horizontal force that can be applied to the lower block so that the two move together is ($g = 10\ \text{m/s}^2$)
Answer: (C) $30$ N
Concept. The top block is accelerated only by friction: $a_{\max} = \mu_sg$.
Step 1. Maximum acceleration. $3\ \text{m/s}^2$.
Step 2. Force. $(2 + 8) \times 3 = 30$ N.
Answer. $30$ N (Option C).
Solution by Sreeraj P, M.Sc Physics