question_answer

A particle has an initial velocity of \[9\text{ }m/s\] due east and a constant acceleration of \[2\text{ }m/{{s}^{2}}\] due west. The distance covered by the particle in the fifth second of its motion is-

A) 0                                 

B) 0.5 m

C) 2m                               

D) none of these

Correct Answer: B

Solution :

  \[\frac{V}{\left( \frac{1}{2} \right)}\,\,=\,\,2\,\,\,\,\,\,\,\,\,\,\,\therefore \,\,v=1\,\,m/s\] Area under the speed time curve from\[t\,\,=\,\,4s\text{ }to\text{ }t\,\,=\,\,5\,\,sec\]. \[r=\left[ \frac{1}{2}\left( \frac{1}{2} \right){{(1)}^{2}} \right]\,\,\times \,\,2\,\,=\,\,0.5\,\,m\]