Question

A block of mass $4kg$ is placed on a rough horizontal plane. A time dependent force $F=K{t}^2$ acts on a block. where $k=2\frac{N}{s^2}$, coefficient of friction $=0.8$. Force of friction between the block and the plane at $t=2S$ is:

• A. $32N$
• B. $4N$
• C. $2N$
• D. $8N$

Answer 1

The correct option is A $32N$

$F=k{g}^2$

At t = 2 sec $F=2\times 4$

$F=8N$

F < friction

$\therefore$ Friction = 8N

$f=\mu mg=0.8\times 4\times 10$

$=32N$