Question

A block of mass 2 kg is kept on the floor. The coefficient of static friction is 0.4. If a force of 2.5 N is applied on the block as shown in the figure, the frictional force between the block and the floor will be

• A. 2.5 N
• B. 5 N
• C. 7.84 N
• D. 10 N

Answer 1

Answer: (A)

2.5 N

Answer 2

Given: $\mu=0.4 \quad F =2.5 N$ $m =2 kg$ $N = mg =20 N$ The max value of friction $=\mu N =0.4 \times 20=8 N$ Since, the force applied is $2.5 N$ there is no need for friction to attain its max. value. $\therefore$ Frictional force $=2.5 N$