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 coefficient of static friction and sliding friction are 0.5 and 0.4 respectively. The acceleration of the body is

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 coefficient of static friction and sliding friction are 0.5 and 0.4 respectively. The acceleration of the body is (A) 6 ms- 2 (B) 4.9 ms- 2 (C) 3.92 ms- 2 (D) 1 ms- 2

Tardigrade Admin · Accepted Answer

Force required to just start the motion is, fL=μ smg Once body starts sliding friction becomes kinetic, Solution

∴ a=(fL - fk/m)=(μ s m g - μ k m g/m) a=((μ )s - (μ )k)g=(0.5 - 0.4)10ms- 2 a=1 ms- 2

Q. A $60 k g$ 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

$6 m s^{- 2}$

$4.9 m s^{- 2}$

$3.92 m s^{- 2}$

$1 m s^{- 2}$

Force required to just start the motion is,
$f_{L} = μ_{s} m g$
Once body starts sliding friction becomes kinetic,

$∴$ $a = \frac{f _{L} - f _{k}}{m} = \frac{μ _{s} m g - μ _{k} m g}{m}$
$a = ((μ)_{s} - (μ)_{k}) g = (0.5 - 0.4) 10 m s^{- 2}$
$a = 1 m s^{- 2}$

Q. 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 coefficient of static friction and sliding friction are 0.5 and 0.4 respectively. The acceleration of the body is

6ms−2

4.9ms−2

3.92ms−2

1ms−2