the acceleration ratio of two masses:
\(a_1 = \frac{M_2-M_1}{M_2+M_1} \times g \)
= \(\frac{2M_1-M_1}{3M_1} \times g\)
then, \(a_2 = \frac{3M_1-M_1}{4M_1} \times g = \frac{g}{2}\)
therefore, \(\frac{a_1}{a_2} = \frac{\frac{g}{3}}{\frac{g}{2}}\)
= \(\frac{2}{3}\)
In the given figure, the blocks $A$, $B$ and $C$ weigh $4\,\text{kg}$, $6\,\text{kg}$ and $8\,\text{kg}$ respectively. The coefficient of sliding friction between any two surfaces is $0.5$. The force $\vec{F}$ required to slide the block $C$ with constant speed is ___ N.
(Given: $g = 10\,\text{m s}^{-2}$) 
Two circular discs of radius \(10\) cm each are joined at their centres by a rod, as shown in the figure. The length of the rod is \(30\) cm and its mass is \(600\) g. The mass of each disc is also \(600\) g. If the applied torque between the two discs is \(43\times10^{-7}\) dyne·cm, then the angular acceleration of the system about the given axis \(AB\) is ________ rad s\(^{-2}\).

Friction is defined as the resistance offered by the surfaces that are in contact when they move past each other.
There are four categories of Friction- static friction, sliding friction, rolling friction, and fluid friction.
In Sliding Friction, the weight of the sliding object calculates the amount of sliding friction present between the two objects. The sliding friction is supposed to be greater as the pressure exerted by the heavy object on the surface it slides over is comparably more.
Friction between a circular object and the surface is called as Rolling Friction. It is required to overcome sliding friction is more than the force required to overcome the rolling friction.
Friction that keeps an object at rest without initiating any relative motion between the body and the surface is termed as Static Friction. For example, a parked car resting on the hill, a hanging towel on the rack. The maximum force of static friction is directly proportional to the normal force.
Fluid Friction is the kind of friction that is exerted by the fluid on the object that is moving through a fluid.