First example: book, m= 0.75 kg, h=1.5 m, g= 9.8 m/s², it has only potential energy Ep,
Ep=m*g*h=0.75*9.8*1.5=11.025 J
Second example: brick, m=2.5 kg, v=10 m/s, h=4 m, it has potential energy Ep and kinetic energy Ek,
E=Ep+Ek=m*g*h + (1/2)*m*v²=98 J + 125 J= 223 J
Third example: ball, m=0.25 kg, v= 10 m/s, it has only kinetic energy Ek
Ek=(1/2)*m*v²=12.5 J.
Fourth example: stone, m=0.7 kg, h=7 m, it has only potential energy Ep,
Ep=m*g*h=0.7*9.8*7=48.02 J
The order of examples starting with the lowest energy:
1. book, 2. ball, 3. stone, 4. brick
Answer:
The explosive force experienced by the shell inside the barrel is 23437500 newtons.
Explanation:
Let suppose that shells are not experiencing any effect from non-conservative forces (i.e. friction, air viscosity) and changes in gravitational potential energy are negligible. The explosive force experienced by the shell inside the barrel can be estimated by Work-Energy Theorem, represented by the following formula:
(1)
Where:
- Explosive force, measured in newtons.
- Barrel length, measured in meters.
- Mass of the shell, measured in kilograms.
,
- Initial and final speeds of the shell, measured in meters per second.
If we know that
,
,
and
, then the explosive force experienced by the shell inside the barrel is:

![F = \frac{(1250\,kg)\cdot \left[\left(750\,\frac{m}{s} \right)^{2}-\left(0\,\frac{m}{s} \right)^{2}\right]}{2\cdot (15\,m)}](https://tex.z-dn.net/?f=F%20%3D%20%5Cfrac%7B%281250%5C%2Ckg%29%5Ccdot%20%5Cleft%5B%5Cleft%28750%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%5Cright%29%5E%7B2%7D-%5Cleft%280%5C%2C%5Cfrac%7Bm%7D%7Bs%7D%20%5Cright%29%5E%7B2%7D%5Cright%5D%7D%7B2%5Ccdot%20%2815%5C%2Cm%29%7D)

The explosive force experienced by the shell inside the barrel is 23437500 newtons.
Complete Question
The complete question is shown on the first uploaded image
Answer:
the value of 
Explanation:
From the question we are told that
The equation is (x + y = 40)
The first value of x is 
The second equation is (0.75x + 1.5y = 40)
So substituting 

=> 
Now substituting y and
into second equation

=> 
So 
The amount of gravitational force between both objects will be the same.
The magnitude of the Earth's gravitational force exerted on the housekeeper is calculated by applying Newton's second law of motion;
F = mg
where;
<em>m </em><em>is the mass of the housekeeper</em>
<em>g </em><em>is acceleration due to gravity</em>
According to Newton's third law of motion, action and reaction are equal and opposite.
The force exerted on the housekeeper by the Earth is equal in magnitude to the force exerted on the Earth by the housekeeper.

The two forces are equal in magnitude but opposite in direction.
Thus, the correct option is " the amount of gravitational force between both objects will be the same"
<em>The</em><em> missing part</em><em> of the </em><em>question </em><em>is below:</em>
a. the Earth exerts the largest amount of gravitational force
b. the housekeeper exerts the largest amount of gravitational force
c. the amount of gravitational force between both objects will be the same
Learn more about Newton's third law of motion here: brainly.com/question/15507