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
$F = Mg$
$F = \mu Mgf$
$Mg \le F \le Mg\sqrt {1 + {\mu ^2}} $
$Mg \ge F \ge Mg\sqrt {1 + {\mu ^2}} $
A bullet of mass $20\, g$ travelling horizontally with a speed of $500 \,m/s$ passes through a wooden block of mass $10.0 \,kg$ initially at rest on a surface. The bullet emerges with a speed of $100\, m/s$ and the block slides $20 \,cm$ on the surface before coming to rest, the coefficient of friction between the block and the surface. $(g = 10\, m/s^2)$
A uniform chain of $6\, m$ length is placed on a table such that a part of its length is hanging over the edge of the table. The system is at rest. The co-efficient of static friction between the chain and the surface of the table is $0.5$, the maximum length of the chain hanging from the table is.......$m.$
A body of weight $50 \,N$ placed on a horizontal surface is just moved by a force of $28.2\, N$. The frictional force and the normal reaction are
Pulling force making an angle $\theta $ to the horizontal is applied on a block of weight $W$ placed on a horizontal table. If the angle of friction is $\alpha $, then the magnitude of force required to move the body is equal to
A football player is moving southward and suddenly turns eastward with the same speed to avoid an opponent. The force that acts on the player while turning is :