Question

A $60kg$ body is pushed with just enough force to start it moving across a floor and the same force continues to act afterwards. The coefficients of static friction and sliding friction are $0.5$ and $0.4$ respectively. The acceleration of the body is
(Take $g=10m/s^2$)

• A. $6m/s^2$
• B. $4.9m/s^2$
• C. $3.92m/s^2$
• D. $1m/s^2$

Answer 1

The correct option is D $1m/s^2$

Limiting friction $={\mu }_{s}N={\mu }_{s}N={\mu }_{s}mg=0.5\times 60\times 10=300N$ Kinetic friction $={\mu }_{k}R={\mu }_{k}mg=0.4\times 60\times 10=240N$ force applied on the body $=300N$ and if the body is moving then,
Net acceleration force $=$ Applied force $-$ Kinetic friction
$ma=300-240=60\therefore a=\frac{60}{60}=1m/s^2$