When two surfaces are coated with a lubricant, then they
Stick to each other
Slide upon each other
Roll upon each other
None of these
What is the maximum value of the force $F$ such that the block shown in the arrangement does not move ....... $N$
A $1.0 kg$ block of wood sits on top of an identical block of wood, which sits on top of a flat level table made of plastic. The coefficient of static friction between the wood surfaces is $\mu_1$, and the coefficient of static friction between the wood and plastic is $\mu_2$. Ahorizontal force $F$ is applied to the top block only, and this force is increased until the top block starts to move. The bottom block will move with the top block if and only if
A block of mass $2\,kg$ moving on a horizontal surface with speed of $4\,ms ^{-1}$ enters a rough surface ranging from $x =0.5\,m$ to $x =1.5\,m$. The retarding force in this range of rough surface is related to distance by $F =- kx$ where $k =12\,Nm ^{-1}$. The speed of the block as it just crosses the rough surface will be ........... $\,ms ^{-1}$
A block of mass $15 \;kg$ is placed on a long trolley. The coefficient of static friction between the block and the trolley is $0.18$. The trolley accelerates from rest with $0.5 \;m s ^{-2}$ for $20 \;s$ and then moves with uniform velocity. Discuss the motion of the block as vlewed by
$(a)$ a stationary observer on the ground,
$(b)$ an observer moving with the trolley.
The rear side of a truck is open and a box of $40 \;kg$ mass is placed $5 \,m$ away from the open end as shown in Figure. The coeffictent of friction between the box and the surface below it is $0.15 .$ On a stratght road, the truck starts from rest and accelerates with $2\; m s ^{-2} .$ At what distance from the starting point does the box fall off the truck? (Ignore the size of the box).