question_answer

A body at rest has mass 10 kg. It is moved by a horizontal force of 5N on a horizontal surface. Calculate the work done by the force in 8s.

Answer:

\[u=0\] \[m=10kg\] \[F=5N\] \[t=8SW=?\] \[W=F\times S\]                               ??????.(1) \[S=\frac{1}{2}a{{t}^{2}}\]                            ??????.(2) \[a=\frac{F}{m}\]                                             ??????.(3) Substituting (2) and (3) in (1), we get \[W=F\times \frac{1}{2}\times \frac{F}{m}\times 8\times 8\]                 \[=\frac{2F}{m}\times \frac{1}{2}\times 64\]                 \[=\frac{5}{10}\times 64=32\,J\]