Answer:
Orbital period, T = 1.00074 years
Explanation:
It is given that,
Orbital radius of a solar system planet, 
The orbital period of the planet can be calculated using third law of Kepler's. It is as follows :

M is the mass of the sun

T = 31559467.6761 s
T = 1.00074 years
So, a solar-system planet that has an orbital radius of 4 AU would have an orbital period of about 1.00074 years.
Wouldn't everything fall?
Mirrors reflect light waves.
Protons
Explanation:
In a neutral atom, the number of electrons equals the number of protons in the atom.
- Electrons are the negatively charge particles in an atom
- Protons carry positive charge.
- Neutrons do not carry any charges.
Protons and neutrons are contained in the nucleus of an atom they determine the mass number of the atom.
In a neutral atom, the number of protons and electrons must be the same.
A charge atom called an ion is one that has lost or gained electrons.
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The feel of weight comes due to the normal reaction force given by the support. Hence, the condition of weightlessness is when the normal reaction force becomes zero. So, during free fall there is no support which can provide the normal reaction. Hence, the bungee jumper feels weightless as she falls towards the earth because of the lack of support force that balances gravity.
Hence, the answer is 3.