Question

A 60 kg body is pushed with just enough force to start it moving across a floor and the same force continues to act afterwards. The coefficient of static friction and sliding friction are 0.5 and 0.4 respectively. The acceleration of the body is

• A. 6 m/s²
• B. 4.9 m/s²
• C. 3.9 m/s²
• D. 1 m/s²

Answer 1

The correct option is D

1 m/s²

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