Answer:
Vrel_jon's = 15 [m/s] to the right
Explanation:
Relative velocity is defined as the relative motion between two bodies, taking into account the directions of motion.
Relative velocity is defined as the relative motion between two bodies, taking into account the directions of motion. The relative velocity is defined as the algebraic sum of the velocities, if the movements are opposite the vectors are subtracted, as will be done below.
Vrel = 20 - 5 = 15 [m/s]
A person watching Jon sees him moving to the right at a speed of 15 [m/s]
This type of a problem can be solved by considering energy transformations. Initially, the spring is compressed, thus having stored something called an elastic potential energy. This energy is proportional to the square of the spring displacement d from its normal (neutral position) and the spring constant k:

So, this spring is storing almost 12 Joules of potential energy. This energy is ready to be transformed into the kinetic energy when the masses are released. There are two 0.2kg masses that will be moving away from each other, their total kinetic energy after the release equaling the elastic energy prior to the release (no losses, since there is no friction to be reckoned with).
The kinetic energy of a mass m moving with a velocity v is given by:

And we know that the energies are conserved, so the two kinetic energies will equal the elastic potential one:

From this we can determine the speed of the mass:

The speed will be 7.74m/s in in one direction (+), and same magnitude in the opposite direction (-).
Explanation:
It is given that,
When a high-energy proton or pion traveling near the speed of light collides with a nucleus, 
Speed of light, 
Let t is the time interval required for the strong interaction to occur. The speed is given by :




So, the time interval required for the strong interaction to occur is
. Hence, this is the required solution.
No velocity will not be changed
Why?
According to Newtons 1st law the velocity of a moving object remains unchanged unless a external force affect that.