Explain -“Static friction force opposes impending motion”.
Consider motion of an acceleration.
Let a box is lying at bottom of compartment of train.
- If box is lying stationary with compartment of train with motion of train, box also will get accelerated.
When train accelerate, friction force acting in horizontal direction will make box to move in direction of train.
If there was no friction, bottom of train would have moved further, box will try to retain its position due to inertia and would collide with rear part of compartment. But this do not happen in day to day life.
Thus, it can be said that static friction force opposes impending motion.
- This impending motion is opposed by static friction force ( $\mathrm{f}_{\mathrm{s}}$ ). This friction force provide equal acceleration in opposite direction of acceleration of train and keep box stationary.
Among the forces in nature, friction can be classified into
A uniform chain of length $L$ which hanges partially from a table, is kept in equilibrium by friction. The maximum length that can withstand without slipping is $l$ , then coefficient of friction between the table and the chain is
Two beads connected by massless inextensible string are placed over the fixed ring as shown in figure. Mass of each bead is $m$ , and there is no friction between $B$ and ring. Find minimum value of coefficient of friction between $A$ and ring so that system remains in equilibrium. ( $C \to $center of ring, $AC$ line is vertical)
A block of mass $4\,kg$ is placed on a rough horizontal plane A time dependent force $F = kt^2$ acts on the block, where $k = 2\,N/s^2$. Coefficient of friction $\mu = 0.8$. Force of friction between block and the plane at $t = 2\,s$ is ....... $N$
Which one of the following statements is incorrect?