I had the same question on a test, the answer is A. Both solar and hydroelectric energy do not emit air pollutants, and although geothermal energy releases some gases, biomass is the biggest polluter.<span>
</span>
D.) It is unlikely that a specific cause can be determined, but the treatment would likely be the same in either case.
Answer:
a.
b.
c.
d. The angular acceleration when sitting in the middle is larger.
Explanation:
a. The magnitude of the torque is given by
, being r the radius, F the force aplied and
the angle between the vector force and the vector radius. Since
and so
.
b. Since the relation
hols, being I the moment of inertia, the angular acceleration can be calculated by
. Since we have already calculated the torque, all left is calculate the moment of inertia. The moment of inertia of a solid disk rotating about an axis that passes through its center is
, being M the mass of the disk. If we assume that a person has a punctual mass, the moment of inertia of a person would be given by
, being
the mass of the person and
the distance from the person to the center. Given all of this, we have
.
c. Similar equation to b, but changing
, so
.
d. The angular acceleration when sitting in the middle is larger because the moment of inertia of the person is smaller, meaning that the person has less inertia to rotate.
<span>For a point mass the moment of inertia is just
the mass times the square of perpendicular distance to the rotation axis, I =
mr^2. That point mass relationship becomes the basis for all other moments of
inertia since any object can be built up from a collection of point masses. So the
I = (1.2 kg)(0.66m/2)^2 = 0.1307 kg m2</span>