An insect crawls up a hemispherical surface very slowly. The coefficient of friction between the insect and the surface is $1/3$. If the line joining the centre of the hemispherical surface to the insect makes an angle $\alpha $ with the vertical, the maximum possible value of $\alpha $ so that the insect does not slip is given by
$\cot \,\alpha = 3$
$\sec \,\alpha = 3$
$\cos ec \,\alpha = 3$
$\cos \,\alpha = 3$
A body of mass $10\,kg$ is moving with an initial speed of $20\,m / s$. The body stops after $5\,s$ due to friction between body and the floor. The value of the coefficient of friction is (Take acceleration due to gravity $g =10\; ms ^{-2}$)
The ratio of acceleration of blocks $A$ placed on smooth incline with block $B$ placed on rough incline is $2: 1$. The coefficient of kinetic friction between block $B$ and incline is .........
A $500 \,kg$ horse pulls a cart of mass $1500\, kg $ along a level road with an acceleration of $1\,m{s^{ - 2}}$. If the coefficient of sliding friction is $0.2$, then the force exerted by the horse in forward direction is ......... $N$
A small block of mass $m$ is projected horizontally with speed $u$ where friction coefficient between block and plane is given by $\mu = cx$, where $x$ is displacement of the block on plane. Find maximum distance covered by the block
What is kinetic friction ? What is rolling friction ?