Answer:
The velocity of the shell when the cannon is unbolted is 500.14 m/s
Explanation:
Given;
mass of cannon, m₁ = 6430 kg
mass of shell, m₂ = 73.8-kg
initial velocity of the shell, u₂ = 503 m/s
Initial kinetic energy of the shell; when the cannon is rigidly bolted to the earth.
K.E = ¹/₂mv²
K.E = ¹/₂ (73.8)(503)²
K.E = 9336032.1 J
When the cannon is unbolted from the earth, we apply the principle of conservation of linear momentum and kinetic energy
change in initial momentum = change in momentum after
0 = m₁u₁ - m₂u₂
m₁v₁ = m₂v₂
where;
v₁ is the final velocity of cannon
v₂ is the final velocity of shell
Apply the principle of conservation kinetic energy
Therefore, the velocity of the shell when the cannon is unbolted is 500.14 m/s
Answer
To understand this concept it is necessary to understand Newton's Second Law
According to Newtons Second law applied force is equal to rate of change of momentum of a body.
Mathematically,
here, 
is rate of change of momentum with respect to time
It means If two eggs fall from same height,one on softer surface and other on hard surface that time the momentum of both eggs will remain equal at both the surfaces. But, impact time will be different. On hard surface egg will stop almost instantly so impact time will be small and hence the force on egg will be large therefore the egg will breakup.
On the other hand on the soft surface like a cotton, egg will not stop instantly but it will slow down for a few seconds and then stop due to which the time of impact will increase. Therefore the force on egg will be less and it won't break up.
Answer:
need Read this excerpt from "Not a Dove, But No Longer a Hawk."
Despite these misgivings, I do not see how we can do anything but continue to prosecute the war. We can and should limit the violence and the suffering being inflicted on the civilians as much as possible, but for whatever reasons, successive Administrations in Washington have carried the commitment in Vietnam to the point where it would be very difficult to prevent any precipitate retreat from degenerating into a rout. If the United States were to disengage from Vietnam under adverse conditions, I believe that the resulting political and psychological shockwaves might undermine our entire position in Southeast Asia.
Which statement best describes the paradox in this excerpt?
The author acknowledges that civilians should not suffer, but states that the civilians must retreat.
The author suggests that the administrators in Washington are busy making policies while overlooking the need to end the war.
The author acknowledges that the violence should stop, but admits that a retreat might have dire consequences.
The author suggests that the Vietnamese people are counting on US support, though their political ideals are not democratic.
Explanation:
The vibration is thermal energy ("heat" energy which every object possesses).
The second one is kinetic energy ("motion" energy of a massive object)
Answer:
680 J
Explanation:
Mechanical energy = potential energy + kinetic energy
ME = PE + KE
ME = mgh + ½ mv²
ME = (77.1 kg) (9.8 m/s²) (0.90 m) + ½ (77.1 kg) (0 m/s)²
ME = 680 J
