<span>We can assume that the horizontal surface has no friction and the pulley is massless. We can use Newton's second law to set up an equation.
F = Ma
F is the net force
M is the total mass of the system
a is the acceleration
a = F / M
a = (mb)(g) / (ma + mb)
a = (6.0 kg)(9.80 m/s^2) / (6.0 kg + 14.0 kg)
a = 58.8 N / 20 kg
a = 2.94 m/s^2
The magnitude of the acceleration of the system is 2.94 m/s^2</span>
(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 However, in this case there is air resistance acting on the plane: this means that the work-energy theorem is no longer valid, because the mechanical energy is not conserved.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
At any crime scene, the two greatest challenges to the physical evidence are contamination and loss of continuity.
<h3>What is the meaning of physical evidence?</h3>
In evidence law, physical evidence (also called real evidence or material evidence) is any material object that plays some role in the matter that gave rise to the litigation, introduced as evidence in a judicial proceeding (such as a trial) to prove a fact in issue based on the object's physical characteristics.
The two types of evidence at crime scenes:
Biological evidence (e.g., blood, body fluids, hair and other tissues)
Latent print evidence (e.g., fingerprints, palm prints, footprints)
The biggest impediment to an investigation is the removal or loss of a piece of evidence from the scene of a crime.
Hence, at any crime scene, the two greatest challenges to the physical evidence are contamination and loss of continuity.
Learn more about the physical evidence here:
brainly.com/question/13505766
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All magnets have north and south poles. Opposite poles are attracted to each other, while the same poles repel each other. When you rub a piece of iron along a magnet, the north-seeking poles of the atoms in the iron line up in the same direction. The force generated by the aligned atoms creates a magnetic field.
