A block of mass m = 2 kg is placed in equilibrium on a moving plank accelerating with acceleration a = 4 m/s2 If coefficient of friction between plank and block μ=0.2 The frictional force acting on the block is:

Question

A block of mass m = 2 kg is placed in equilibrium on a moving plank accelerating with acceleration a = 4 m/s2 If coefficient of friction between plank and block μ=0.2 The frictional force acting on the block is: (A) 8 N (B) 6 N (C) zero (D) 4 N

Tardigrade Admin · Accepted Answer

Driving force w.r.t. platform = ma =2 × 4=8 N And resisting force =f textlim = μ N =0.2× 2 × 10 =4 N Here resisting force is sufficient to keep the block at rest w.r.t plank hence the block will slide on plank and friction force will be 4 N

Q. A block of mass $m = 2 k g$ is placed in equilibrium on a moving plank accelerating with acceleration $a = 4 m / s^{2}$ If coefficient of friction between plank and block $μ = 0.2$ The frictional force acting on the block is:

$8 N$

$6 N$

zero

$4 N$

Driving force w.r.t. platform = ma

$= 2 \times 4 = 8 N$

And resisting force $= f_{lim} = μ N$

$= 0.2 \times 2 \times 10 = 4 N$

Here resisting force is sufficient to keep the block at rest w.r.t plank hence the block will slide on plank and friction force will be $4 N$

Q. A block of mass m=2kg is placed in equilibrium on a moving plank accelerating with acceleration a=4m/s2 If coefficient of friction between plank and block μ=0.2 The frictional force acting on the block is:

8N

6N