A rough vertical board has an acceleration ‘a’ so that a 2 kg block pressing against it

English

Gujarati

Hindi

4-2.Friction

medium

A rough vertical board has an acceleration $‘a’$ so that a $2$ kg block pressing against it does not fall. The coefficient of friction between the block and the board should be

A

$ > g/a$

B

$ < g/a$

C

$ = g/a$

D

$ > a/g$

Solution

(a) For the limiting condition upward friction force between board and block will balance the weight of the block.

i.e. $F > mg$

==> $\mu (R) > mg$

==> $\mu (ma) > mg$

==> $\mu > \frac{g}{a}$

Standard 11

Physics

Share

Similar Questions

A block of mass $m$ is in contact with the cart $C$ as shown in the figure. The coefficient of static friction between the block and the cart is $\mu .$ The acceleration $\alpha$ of the cart that will prevent the block from falling satisfies

medium

(AIPMT-2010)

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).

hard

$A$ block of mass $M$ is placed on $a$ horizontal surface and it is tied with an inextensible string to $a$ block of mass, as shown in figure. A block of mass $m_0$ is also placed on $M$ If there is no friction between any two surfaces, then

hard

Two block $(A)\,2\,kg$ and $(B)\,5\,kg$ rest one over the other on a smooth horizontal plane. The cofficient of static and dynamic friction between $(A)$ and $(B)$ is the same and equal to $0.60$. The maximum horizontal force that can be applied to $(B)$ in order that both $(A)$ and $(B)$ do not have any relative motion : $(g = 10\,m/s^2)$

medium

Imagine $a$ situation in which the horizontal surface of block $M_0$ is smooth and its vertical surface is rough with $a$ coefficient of friction $\mu$ Identify the correct statement $(s)$

hard