Which is a suitable method to decrease friction
Ball and bearings
Lubrication
Polishing
All the above
A block of mass $2 kg$ slides down an incline plane of inclination $30^o$. The coefficient of friction between block and plane is $0.5$. The contact force between block and plank is :
A block of mass $2 \,kg$ rests on a rough inclined plane making an angle of $30°$ with the horizontal. The coefficient of static friction between the block and the plane is $ 0.7$. The frictional force on the block is ....... $N$.
The maximum static frictional force is
Figure shows a man standing stationary with respect to a horizontal conveyor belt that is accelerating with $1\; m s^{-2}$. What is the net force on the man? If the coefficient of static friction between the man’s shoes and the belt is $0.2$, up to what acceleration of the belt can the man continue to be stationary relative to the belt? (Mass of the man $= 65 \;kg.)$
Which of the following is self adjusting in nature?