Laws Of Motion Question 151
Question: A body of mass $ M $ is kept on a rough horizontal surface (friction coefficient $ \mu $ ). A person is trying to pull the body by applying a horizontal force but the body is not moving. The force by the surface on the body is $ F $ , where
Options:
A) $ F=mg $
B) $ F=\mu Mgf $
C) $ Mg\le F\le Mg\sqrt{1+{{\mu }^{2}}} $
D) $ Mg\ge F\ge =\mu Mg\sqrt{1+{{\mu }^{2}}} $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] Maximum force by surface when friction works $ \sqrt{f^{2}+R^{2}}=\sqrt{{{(\mu R)}^{2}}+R^{2}}=R\sqrt{{{\mu }^{2}}+1} $ Minimum force = R when there in no friction Hence, ranging from R to $ R\sqrt{{{\mu }^{2}}+1} $ we get, $ mg\le F\le mg\sqrt{{{\mu }^{2}}+1} $
