Answer : The final energy of the system if the initial energy was 2000 J is, 3500 J
Solution :
(1) The equation used is,

where,
= final internal energy
= initial internal energy
q = heat energy
w = work done
(2) The known variables are, q, w and 
initial internal energy =
= 2000 J
heat energy = q = 1000 J
work done = w = 500 J
(3) Now plug the numbers into the equation, we get

(4) By solving the terms, we get




(5) Therefore, the final energy of the system if the initial energy was 2000 J is, 3500 J
what are the answer choices?
Answer:
a
The height is 
b
The horizontal distance is 
Explanation:
From the question we are told that
The speed is 
The angle is 
The height of the cannon from the ground is h = 2 m
The distance of the net from the ground is k = 1 m
Generally the maximum height she reaches is mathematically represented as

=> ![H = \frac{(15)^2 [sin (40)]^2 }{2 * 9.8} + 2](https://tex.z-dn.net/?f=H%20%20%3D%20%20%5Cfrac%7B%2815%29%5E2%20%5Bsin%20%2840%29%5D%5E2%20%7D%7B2%20%2A%209.8%7D%20%20%2B%20%202)
=> 
Generally from kinematic equation

Here s is the displacement which is mathematically represented as
s = [-(h-k)]
=> s = -(2-1)
=> s = -1 m
There reason why s = -1 m is because upward motion canceled the downward motion remaining only the distance of the net from the ground which was covered during the first half but not covered during the second half
a = -g = -9.8

So

=> 
using quadratic formula to solve the equation we have

Generally distance covered along the horizontal is

=> 
=> 
The scientist is likely to be studying kinematics.
Kinematics is the branch of science, specifically physics, which is concerned with the motion of objects without reference to the forces that induce this motion. An example of kinematics is studying the change in velocity of an object over time or the distance covered by an object in a specified amount of time.
<span>The
thermal energy found in a piece of coal is lesser than in the thermal energy in
a newly opened coal mine. The newly opened coal mine requires a greater thermal
energy to really open it due to its solid structure. Whereas in a piece of
coal, it only requires a lesser amount of thermal energy to extract it.</span>