Laws Of Motion Question 351
Question: A block weighs W is held against a vertical wall by applying a horizontal force F. The minimum value of F needed to hold the block is[MP PMT 1993]
Options:
A) Less than W
B) Equal to W
C) Greater than W
D) Data is insufficient
Show Answer
Answer:
Correct Answer: C
Solution:
Here applied horizontal force F acts as normal reaction. For holding the block Force of friction = Weight of block $ f=W $ therefore $ \mu R=W $ therefore$ \mu F=W $
therefore $ F=\frac{W}{\mu } $ As $ \mu <1 $
$ \therefore \ \ \ F>W $
