question_answer

A particle moves towards east for 2 s with velocity 15 m/s and move towards north for 8s with velocity 5 m/s. Then, average velocity of the particle is

A)  1 m/s             

B)         5 m/s

C)  7 m/s             

D)         10 m/s

Correct Answer: B

Solution :

Distance \[AB=2\times 15=30\,m\] Distance \[BC=8\times 5=40\,m\] Displacement \[(AC)=\sqrt{{{(AB)}^{2}}+{{(BC)}^{2}}}\]       \[=\sqrt{{{(30)}^{2}}+{{(40)}^{2}}}\]       \[=50\,m\] Total time of travel = 2 + 8 = 10 sec. \[\therefore \] Average velocity \[(V)=\frac{50}{10}=5\]m/sec.