In this entry we show you some exercises and their solutions to check your level in the subject of Physics. We show you the following links in case they are of interest to you:
PHYSICS PROBLEMS
1 Exercise
A satellite of mass m=500 kg orbits around the Earth at a distance R=7×10^6 m from the center of the Earth.
a) Calculate the gravitational force between the satellite and the Earth.
b) Calculate the gravitational field due to the Earth at the position of the satellite.
Data:
- Earth mass: M=5.972×10^{24} kg
- Gravitational constant: G=6.674×10^{−11} Nm^2/kg^2
2 Exercise
A point charge q=5×10^{−6} C is in a vacuum.
a) Calculate the electric field at a distance r = 0.05 m of the load
b) If a test load is placed q′=2×10^{−6} C At that point, what force would I experience?
Data:
- Vacuum permissiveness constant: ϵ_0=8.854×10^{−12} C^2/N⋅m^2
SOLUTIONS
1 Exercise
a) Newton's law of universal gravitation is:
F=\frac{G⋅m⋅M}{R^2}
We substitute values:
We calculate and obtain:
F≈3642.5N
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b) The gravitational field g due to the Earth at a point is:
g=\frac{F}{m}
We use the value of F from the previous section:
g=\frac{3642.5 N}{500 kg}g≈7.285 m/s^2
2 Exercise
a) The electric field E due to a point charge is E= \frac{kq }{r^2}
Where k=\frac{1}{4πε_0}
We substitute values: E=\frac{9×10^9N⋅m^2/C^2×5×10^{−6}C}{(0.05 m)^2}
E≈ 1800 N/C
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b) The electric force F on a charge in an electric field is:
F=q′×E
We substitute values: F= 2×10^{−6} C×1800 N/C
F≈ 0.0036 N