question_answer

A particle is moving eastward with a velocity 10 m/s. In 10 s the velocity changes to 10 m/s northwards. The average acceleration during this time is:

A) \[\sqrt{2}\,m/{{s}^{2}}N-W\]         

B) \[\frac{1}{2}\,m/{{s}^{2}}\,N-W\]

C) \[\sqrt{2}\,m/{{s}^{2}}\,N-E\]        

D)  0  

Correct Answer: A

Solution :

Average accelerations\[=\frac{\Delta \vec{v}}{\Delta t}=\frac{|{{{\vec{v}}}_{2}}-{{{\vec{v}}}_{1}}|}{\Delta t}\] \[\therefore \]Magnitude of average acceleration \[=\frac{10\sqrt{2}}{10}=\sqrt{2}\frac{m}{{{s}^{2}}}NW.\] Hence, the correction option is [c].