Question

A body of mass $2 \,kg$ is placed on rough horizontal plane. The coefficient of friction between body and plane is $0.2$. Then:

• A. body will move in forward direction if $F=5N$
• B. body will move in backward direction with acceleration $0.5\text{ }m/{{s}^{2}},$ if force $F=3N$
• C. If $F=3N,$ then body will be in rest condition
• D. both [a] & [c] are correct

Answer 1

Answer: (D)

both [a] & [c] are correct

Answer 2

For moving the body, applied force should be greater or equal to limiting friction (i.e. $\mu N$ ). The limiting friction is $f_{2} =\mu N$ $=\mu mg$ $=0.2 \times 2 \times 9.8=3.92\, N$ (a) Since applied force $F=5\, N$, so, body starts to move- in f?ward direction. (b) Here, applied force is lesser than limiting friction. So, body does not move. (c) The reason is same as (b). Hence (d) is correct.