MCQ
A body of weight $64\, N$ is pushed with just enough force to start it moving across a horizontal floor and the same force continues to act afterwards. If the coefficients of static and dynamic friction are $0.6$ and $0.4$ respectively, the acceleration of the body will be (Acceleration due to gravity $= g$)
  • A
    $\frac{g}{{6.4}}$
  • B
    $0.64\, g$
  • C
    $\frac{g}{{32}}$
  • $0.2\, g$

Answer

Correct option: D.
$0.2\, g$
d
(d) Weight of the body $= 64\,N$

so mass of the body $m = 6.4\;kg$,   ${\mu _s} = 0.6$, ${\mu _k} = 0.4$

Net acceleration $ = \frac{{{\rm{Applied\, force - Kinetic\, friction}}}}{{{\rm{Mass\, of\, the \,body}}}}$

$ = \frac{{{\mu _s}mg - {\mu _k}mg}}{m} = ({\mu _s} - {\mu _k})g = (0.6 - 0.4)g = 0.2\,g$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A particle executing simple harmonic motion along $y-$axis has its motion described by the equation $\text{y}=\text{A}\sin(\omega\text{t})+\text{B}$ The amplitude of the simple harmonic motion is:
A car changes speed from $18\,km/h$ to $36\,km/h$ in $5\,s$. The diameter of its wheel is $0.8\,m$ . The angular acceleration of the wheel is ........ $rad/s^2$
A mass is revolving in a circle, which is in the plane of the paper. The direction of angular acceleration if any, is:
A vessel of volume $V$ contains a mixture of $1$ mole of hydrogen and $1$ mole of oxygen $($both considered as ideal$).$ Let $f_1\text{(v)dv}$ denotes the fraction of molecules with speed between $v$ and $(v + dv)$ with $f_2\text{(v)dv}$, similarly for oxygen. Then,
The potential difference applied to an $X-$ray tube is increased. As a result, in the emitted radiation:
A car moves towards north at a speed of $54 \,km / h$ for $1 \,h$. Then it moves eastward with same speed for same duration. The average speed and velocity of car for complete journey is ..........
A rope of negligible mass is wound round a hollow cylinder of mass $3\, kg$ and radius  $40\, cm$. If rope is pulled with a force of $30\, N$, then the angular acceleration  produced in the cylinder is ........ $rad\, s^{-2}$.
The angular velocity of the earth with which it has to rotate so that acceleration due to gravity on $60^o$ latitude becomes zero is (Radius of earth $= 6400\, km$. At the poles $g = 10\,m{s^{ - 2}})$
A block of mass $m$ lying on a rough horizontal plane is acted upon by a horizontal force $P$ and another force $Q$ inclined an at an angle $\theta $ to the vertical. The minimum value of coefficient of friction between the block and the surface for which the block will remain in equilibrium is
A healthy adult of height $1.7 \,m$ has an average blood pressure $( BP )$ of $100 \,mm$ of $Hg$. The heart is typically at a height of $1.3 \,m$ from the foot. Take, the density of blood to be $10^3 \,kg / m ^3$ and note that $100 \,mm$ of $Hg$ is equivalent to $13.3 \,kPa$ (kilo pascals). The ratio of $BP$ in the foot region to that in the head region is close to