question_answer

A particle moves towards east for 2 sec with velocity 15 m/s and move towards north for 8 sec 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 convered towards east \[=2\times 15\,=30\,m\] Distance covered towards north \[=8\times 5\,=40\,m\] Total displacement\[=\sqrt{{{40}^{2}}+{{30}^{2}}}=50\,m\] Average velocity\[\text{=}\frac{\text{total}\,\text{displacement}}{\text{total}\,\text{time}}\]                                             \[=\frac{50}{2+8}=5\,m/s\]