Laws Of Motion Question 405
Question: A block A is kept on a block B. Friction between B and ground is negligible. $ {{\mu } _{s}} $ and $ {{\mu } _{K}} $ are the coefficients of static and kinetic friction between A and B, respectively. A horizontal force F is applied on A. $ a _{1} $ is the acceleration of B just before A slips on B and $ a _{2} $ is the acceleration of B after A slips on B. Assume $ {{\mu } _{s}}>{{\mu } _{K}} $ . Then
Options:
A) $ a _{1}>a _{2} $
B) $ a _{1}<a _{2} $
C) $ a _{1}=a _{2} $
D) None of these
Show Answer
Answer:
Correct Answer: A
Solution:
Just before slipping occurs force acting on B is,$ {{\mu } _{s}}mg $ , where m is the mass of block A. After the slipping the force on block B is $ {{\mu } _{K}}mg $ .
Force before slipping is more, so acceleration before slipping should be more.
