Question

A block of mass $5kg$ is kept on a horizontal floor having coefficient of friction $0.09$. Two mutually perpendicular horizontal force of $3N$ and $4N$ act on this block. The acceleration of the block is: $(g=10m/s^2)$

• A. $zero$
• B. $0.1m/s^2$
• C. $0.2m/s^2$
• D. $0.3m/s^2$

Answer 1

The correct option is B $0.1m/s^2$

Given,

Mass of block, $m=5kg$

Coefficient of friction $\mu =0.09$

Two forces $F_1=3N\&F_2=4N$

Resultant force $F_{net}=\sqrt{F_1^2+F_2^2}=\sqrt{3^2+4^2}=5N$

Friction force $F_R=\mu mg=0.09\times 5\times 10=4.5N$

Acceleration of block, $a=\frac{F_{net}-F_R}{m}=\frac{5-4.5}{5}=0.1m/s^2$

Hence, the acceleration of the block is $0.1m/s^2$