question_answer

A force acts for 8 seconds on a body of mass 10 kg. The force then stops acting and the body describes 80 m in the next 5s. Find the force.

Answer:

\[t=8s\]                                                \[m=10\,kg\] After the force stops acting, the body moves with a uniform velocity (v) given by \[v=\frac{dis\tan ce\,\,travelled}{time\,taken}=\frac{80}{5}m/s\] Now, Applying v = u + at \[\Rightarrow 16=0+a\times 8\]                                \[(\because u=0)\] \[\Rightarrow a=2m/{{s}^{2}}\] \[\therefore F=ma=10\times 2=20N\]