A block of mass 1 kg is held at rest against a rough vertical surface by pushing by a force F horizontally. The coefficient of friction is 0.5. When

Question

A block of mass 1 kg is held at rest against a rough vertical surface by pushing by a force F horizontally. The coefficient of friction is 0.5. When (A) F = 40 N friction on the block is 20 N. (B) F = 30 N, friction on the block is 10 N. (C) F = 20 N, friction on the block is 10 N. (D) Minimum value of force F to keep block at rest is 20 N.

Tardigrade Admin · Accepted Answer

Minimum value of force F to keep block at rest μ F = mg ( F = N ) ⇒ 0.5 F =0.1 × 10 ⇒ F =20 N That means if F ≥ 20 N friction will be equal to mg (10 N ) <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/04eb2abab956f5c6b101180883320dc6-.png" />

Q. A block of mass $1 k g$ is held at rest against a rough vertical surface by pushing by a force F horizontally. The coefficient of friction is $0.5.$ When

F = 40 N friction on the block is 20 N.

F = 30 N, friction on the block is 10 N.

F = 20 N, friction on the block is 10 N.

Minimum value of force F to keep block at rest is 20 N.

Minimum value of force $F$ to keep block at rest
$μ F = m g (F = N)$
$\Rightarrow 0.5 F = 0.1 \times 10$
$\Rightarrow F = 20 N$
That means if $F \geq 20 N$ friction will be equal to $m g (10 N)$

Q. A block of mass 1kg is held at rest against a rough vertical surface by pushing by a force F horizontally. The coefficient of friction is 0.5. When