Answer:
If the rifle is held loosely away from the shoulder, the recoil velocity will be of -8.5 m/s, and the kinetic energy the rifle gains will be 81.28 J.
Explanation:
By momentum conservation, <em>and given the bullit and the recoil are in a straight line</em>, the momentum analysis will be <em>unidimentional</em>. As the initial momentum is equal to zero (the masses are at rest), we have that the final momentum equals zero, so
now we clear 
and use the given data to get that
<em>But we have to keep in mind that the bullit accelerate from rest to a speed of 425 m/s</em>, then <u>if the rifle were against the shoulder, the recoil velocity would be a fraction of the result obtained</u>, but, as the gun is a few centimeters away from the shoulder, it is assumed that the bullit get to its final velocity, so the kick of the gun, gets to its final velocity 
too.
Finally, using we calculate the kinetic energy as
The answer would be 187.95 kg.m/s.
To get the momentum, all you have to do is multiply the mass of the moving object by the velocity.
p = mv
Where:
P = momentum
m = mass
v = velocity
Not the question is asking what is the total momentum of the football player and uniform. So we need to first get the combined mass of the football player and the uniform.
Mass of football player = 85.0 kg
Mass of the uniform = <u> 4.5 kg</u>
TOTAL MASS 89.5 kg
So now we have the mass. So let us get the momentum of the combined masses.
p = mv
= (89.5kg)(2.1m/s)
= 187.95 kg.m/s
Its B polaris seems smaller than the Sun
I think d because the water can make the humidity go down and make the air cool
<span>Keplers second law, that gravitational potential energy is lost when planets get near the sun and it becomes kinetic energy, best describes the reason why a planets speed will increase as it becomes closer to the sun.</span>
