(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 However, in this case there is air resistance acting on the plane: this means that the work-energy theorem is no longer valid, because the mechanical energy is not conserved.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
When a liquid changes to gas, this phase change is called vaporization or evaporization.
1. Average time for the first 0.25 m: 2.23 s
Explanation:
The average time that it takes for the car to travel the first 0.25 m is given by the average of the first three measures, so:
2. Average time to travel between 0.25 m and 0.50 m: 0.90 s
Explanation:
First of all, we need to calculate the time the car takes to travel between 0.25 m and 0.50 m for each trial:
t1 = 3.16 s - 2.24 s = 0.92 s
t2 = 3.08 s - 2.21 s = 0.87 s
t3 = 3.15 s - 2.23 s = 0.92 s
So, the average time is
3. Velocity in the second 0.25 m section: 0.28 m/s
Explanation:
The average velocity in the second 0.25 m section is equal to the ratio between the distance covered (0.25 m) and the average time taken (0.90 s):
Its axis is tilted on the side.
Answer:
The digestive system provides nutrients to the body by breaking down food.