A cyclist speeding at $18 \;km/h$ on a level road takes a sharp circular turn of radius $3\; m$ without reducing the speed. The co-efficient of static friction between the tyres and the road is $0.1$. Will the cyclist slip while taking the turn?
On an unbanked road, frictional force alone can provide the centripetal force needed to keep the cyclist moving on a circular turn without slipping. If the speed is too large, or if the turn is too sharp (i.e. of too small a radius) or both, the frictional force is not sufficient to provide the necessary centripetal force, and the cyclist slips. The condition for the cyclist not to slip is given by Equation
$v^{2} \leq \mu_{s} R g$
Now, $R=3 \,m g=9.8 \,m s ^{-2}, \mu_{s}=0.1 .$ That $1\, s$
$\mu_{s} R g=2.94\, m ^{2}\, s ^{-2}, v=18 \,km / h =5 \,ms ^{-1} $
$i.e.\;\;v^{2}=25 \,m ^{2} \,s ^{-2} .$ The condition is not obeyed. The cyclist will slip while taking the circular turn.
The limiting value of static friction between two contact surfaces is ...........
A block of mass $2 \,kg$ is kept on the floor. The coefficient of static friction is $0.4$. If a force F of $2.5$ Newtons is applied on the block as shown in the figure, the frictional force between the block and the floor will be ........ $N$
$Assertion$ : On a rainy day it is difficult to drive a car or bus at high speed.
$Reason$ : The value of coefficient of friction is lowered due to wetting of the surface
A block of wood resting on an inclined plane of angle $30^o$, just starts moving down. If the coefficient of friction is $0.2$, its velocity (in $ms^{-1}$) after $5\, seconds$ is : $(g = 10\, ms^{-2})$
When two surfaces are coated with a lubricant, then they