When we say that the weight of an object is Mg, and that g = 9.8 N/kg, what assumptions are we making?
Which of the below?
-The distribution of mass in the earth is spherically symmetric.
-The density of the earth is the same everywhere.
-The earth's interior is solid everywhere.
-The orbit of the earth is circular and not elliptical.
-We neglect the effect of astronomical bodies other than the earth.
-The object is at the earth's surface.
-Two significant figures are sufficient.
-Newton's law of gravitation holds.
-The distribution of mass in the earth is spherically symmetric.
Yes, if all the mass were under Paris, g would be very high there.
-The density of the earth is the same everywhere.
No, all the mass could be at the center
-The earth's interior is solid everywhere.
No, again all the mass could be at center
-The orbit of the earth is circular and not elliptical.
Not relevant
-We neglect the effect of astronomical bodies other than the earth.
Yes
-The object is at the earth's surface.
Yes
-Two significant figures are sufficient.
Yes
-Newton's law of gravitation holds.
Yes
When we say that the weight of an object is Mg and that g = 9.8 N/kg, we are making several assumptions. The correct assumptions among the options you provided are:
1. The distribution of mass in the Earth is spherically symmetric: This assumption implies that the Earth can be treated as a uniform sphere when calculating the gravitational force acting on an object.
2. The density of the Earth is the same everywhere: This assumption allows us to assume a constant mass distribution throughout the Earth when calculating the gravitational force.
3. We neglect the effect of astronomical bodies other than the Earth: This assumption disregards the gravitational influence of other celestial bodies, such as the Moon or nearby planets, on the object's weight.
4. The object is at the Earth's surface: This assumption implies that the object is not at an altitude or depth significant enough to affect the calculation of its weight.
5. Newton's law of gravitation holds: This assumption states that the gravitational force between two objects is directly proportional to their masses and inversely proportional to the square of the distance between their centers of mass.
The assumptions not included from the options are:
- The Earth's interior is solid everywhere: This assumption is not explicitly made when calculating the weight of an object. The state of the Earth's interior does not affect the gravitational force acting on an object at its surface.
- The orbit of the Earth is circular and not elliptical: This assumption is unrelated to calculating the weight of an object. The shape of the Earth's orbit does not affect the relationship between an object's mass and its weight.