A force of $5\, N$ acts on a $15\, kg$ body initially at rest. The work done by the force during the first second of motion of the body is
A force of $5\, N$ acts on a $15\, kg$ body initially at rest. The work done by the force during the first second of motion of the body is
$5 \,J$
$\frac{5}{6}J$
$6\, J$
$75\,J$
A force of $5\, N$ acts on a $15\, kg$ body initially at rest. The work done by the force during the first second of motion of the body is
$W = Fs = F \times \frac{1}{2}a{t^2}$
$\left[ {{\rm{from}}\;s = ut + \frac{1}{2}a{t^2}} \right]$
==> $W = F\left[ {\frac{1}{2}\left( {\frac{F}{m}} \right)\;{t^2}} \right]$
$ = \frac{{{F^2}{t^2}}}{{2m}} = \frac{{25 \times {{(1)}^2}}}{{2 \times 15}} = \frac{{25}}{{30}} = \frac{5}{6}\;J$
Other Language