Question

A block of mass $2kg$ is placed on the floor. The coefficient of static friction is $0.4$. Force of $2.8N$ is applied on the block. The force of friction between the block and the floor is (Taken $g=10m/s^2$)

• A. 2.8 N
• B. 8 N
• C. 2.0 N
• D. zero

Answer 1

Answer: (A)

2.8 N

The maximum static frictional force is $\mu mg=0.4\times 2\times 10=8N$, which is more than the applied force.

So, when a force of $2.8N$ is applied, static frictional force is also $2.8$ N, as it is a self-adjusting force.