how many helium-filled balloons would it take to lift a person? assume the person has a mass of 73 kgkg and that each helium-fil
1 answer:
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The new gravitation force at the new location is 40 N
Explanation:
The weight of the astronaut is given by the equation
(1)
where
m is the mass of the astronaut
g is the acceleration of gravity
The acceleration of gravity at a certain distance from the centre of the Earth is given by
where G is the gravitational constant and M is the Earth's mass. So we can rewrite eq.(1) as
When the astronaut is on the Earth's surface, (where R is the Earth's radius), so his weight is
Later, he moves to another location where his distance from the Earth's surface is 3 times the previous distance, so the new distance from the Earth's centre is
Therefore, the new weight is
Which means that his weight has decreased by a factor 16: therefore, the new weight is
Learn more about gravitational force:
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Answer:
4.71 eV
Explanation:
For an electromagnetic wave with wavelength
the energy of the photons in the wave is given by
where h is the Planck constant and c the speed of light. Therefore, this is the minimum energy that a photon should have in order to extract a photoelectron from the copper surface.
The work function of a metal is the minimum energy required by the incident light in order to extract photoelectrons from the metal's surface. Therefore, the work function corresponds to the energy we found previously. By converting it into electronvolts, we find: