Physics-
General
Easy
Question
A block P of mass m is placed on a frictionless horizontal surface. Another block Q of same mass is kept on P and connected to the wall with the help of a spring of spring constant k as shown in the figure. 
is the coefficient of friction between P and Q. The blocks move together performing SHM of amplitude A. The maximum value of the friction force between P and Q is
- Zero
The correct answer is:
When two blocks performs simple harmonic motion together then at the extreme position ( at amplitude =A)Restoring force 
Þ 
There will be no relative motion between P and Q if pseudo force on block P is less than or just equal to limiting friction between P and Q.
i.e. 
Limiting friction
Maximum friction 
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