question_answer

A proton in a cyclotron changes its velocity from 30 km/s north to 40 km/s east in 20s. What is the magnitude of average acceleration during this time?

A)  \[2.5\text{ }km/{{s}^{2}}\]      

B)  \[12.5\text{ }km/{{s}^{2}}\]

C)  \[22.5\text{ }km/{{s}^{2}}\]    

D)  \[32.5\text{ }km/{{s}^{2}}\]

Correct Answer: A

Solution :

 Change in velocity\[=\sqrt{{{(40)}^{2}}+{{(30)}^{2}}}\]     \[=50\text{ }km/s\] Average acceleration\[=\frac{50}{20}\] \[=2.5\text{ }km/{{s}^{2}}\]