Ke = (1/2)mv²
m = 100kg, v = 10 km/s = 10*1000 = 10000m/s
Ke = (1/2)*100*10000
Ke = 500000 Joules
The conservation of momentum states that the total momentum in a system is constant if there is no external force acting on the system. The total momentum in the gun bullet system is 0 so it must stay that way.
The momentum of the bullet is mv = 0.015*500=7.5
The momentum of the gun must be the same to keep the total momentum of the system equal to zero, so we know that p = 7.5 for the gun.
Substituting this in we get:
7.5=3.1x
x=7.5/3.1
x=2.42
So the speed of the gun is 2.4m/s.
Momentum = mass • velocity
v= 17.5/2.5
= 7 m/s
Answer:
The number of people at game are approximately 22909
Explanation:
Given data
When one person shout 
When n number of person shout together 
The sound intensity level during one person shout is given by:

The sound intensity level during n number of person shout is given by:

Since each person generates same sound intensity and hence total number of persons can be determined as

Hence
The number of people at game are approximately 22909
Radioactive decay in the core releases energy. When the sun matter is heated it reduced in density and rises to the surface of the sun, meaning the energy is transferred to the surface.