A net force of 60 N north acts on an object with a mass of 30 kg. Use Newton's second law of
1 answer:
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Answer:
The correct answer is
Explanation:
The formula for the electron drift speed is given as follows,
where n is the number of of electrons per unit m³, q is the charge on an electron and A is the cross-sectional area of the copper wire and I is the current. We see that we already have A , q and I. The only thing left to calculate is the electron density n that is the number of electrons per unit volume.
Using the information provided in the question we can see that the number of moles of copper atoms in a cm³ of volume of the conductor is . Converting this number to m³ using very elementary unit conversion we get
. If we multiply this number by the Avagardo number which is the number of atoms per mol of any gas , we get the number of atoms per m³ which in this case is equal to the number of electron per m³ because one electron per atom of copper contribute to the current. So we get,
if we convert the area from mm³ to m³ we get .So now that we have n, we plug in all the values of A ,I ,q and n into the main equation to obtain,
which is our final answer.
Planet A;
m = the mass
Let r = the radius
Planet B:
Let M = the mass
The radius is 2r (twice the radius of planet A)
The surface gravitational acceleration of planets A and B (they have the same surface gravity) are
Answer: The mass of planet B is 4m.
m = the mass
Let r = the radius
Planet B:
Let M = the mass
The radius is 2r (twice the radius of planet A)
The surface gravitational acceleration of planets A and B (they have the same surface gravity) are
Answer: The mass of planet B is 4m.