(a) No, because the mechanical energy is not conserved
Explanation:
The work-energy theorem states that the work done by the engine on the airplane is equal to the gain in kinetic energy of the plane:
(1)
However, this theorem is only valid if there are no non-conservative forces acting on the plane. However, in this case there is air resistance acting on the plane: this means that the work-energy theorem is no longer valid, because the mechanical energy is not conserved.
Therefore, eq. (1) can be rewritten as
which means that the work done by the engine (W) is used partially to increase the kinetic energy of the airplane () and part is lost because of the air resistance ().
(b) 77.8 m/s
First of all, we need to calculate the net force acting on the plane, which is equal to the difference between the thrust force and the air resistance:
Now we can calculate the acceleration of the plane, by using Newton's second law:
where m is the mass of the plane.
Finally, we can calculate the final speed of the plane by using the equation:
where
is the final velocity
is the initial velocity
is the acceleration
is the distance travelled
Solving for v, we find
True because molecules don't have to be compounds but compounds have to be molecules
<span>While you're going to the store, your acceleration changes. Some times it increases your overall speed sometimes it reduces it. Constant acceleration does not occur because it would mean that you would constantly accelerate and eventually go past the store. Even reduction of speed is a type of acceleration in physics. When you reach it, we can then calculate how much your velocity was on average and analyze how changing acceleration would've affected it.</span>
Answer:
Pluto's orbit brings it inside the orbit of <u>Neptune</u>.