Hiya!
The answer to your question is B.
Physical Properties.
~Hope this helps~
Explanation:
Given that,
Mass of the object, m = 7.11 kg
Spring constant of the spring, k = 61.6 N/m
Speed of the observer, 
We need to find the time period of oscillation observed by the observed. The time period of oscillation is given by :

Time period of oscillation measured by the observer is :

So, the time period of oscillation measured by the observer is 5.79 seconds.
Answer:

Explanation:
F = Force = 
m = Mass of proton = 
t = Time taken = 
Acceleration is given by


The velocity of the proton is 