(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 However, in this case there is air resistance acting on the plane: this means that the work-energy theorem is no longer valid, because the mechanical energy is not conserved.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
Answer:
The velocity of the rocket is 7.8 m/s
Explanation:
Answer:
The answer is false
Explanation:
Though the mostly used SI unit of measurement or the most popular units are the
Length,
Time and
Mass
i.e meter (m), seconds (s), kilogram (kg)
Aside all the above stated units for measurements there are other four basic units which are itemized bellow.
they are
1. Amount of substance - mole (mole)
2. Electric current - ampere (A)
3. Temperature - kelvin (K)
4. Luminous intensity - candela (cd)
Answer: D. They are the coldest stars.
Explanation:
Answer:
The force will be 54.0 units
Explanation:
The magnitude of the electrostatic force between two charged objects is given by Coulomb's Law:
where
k is Coulomb's constant
q1, q2 are the magnitude of the two charges
r is the separation between the two charges
From the equation, we see that the magnitude of the force is directly proportional to the charge of object 2:
In this problem, the initial force between the two objects is
F = 18.0 N
And so, when the charge on object 2 is tripled,
The new electrostatic force will be
So, the force will also triple: since the original force was 18.0 units, the new force will be