Answer:
a) 0.138J
b) 3.58m/S
c) (1.52J)(I)
Explanation:
a) to find the increase in the translational kinetic energy you can use the relation

where Wp is the work done by the person and Wg is the work done by the gravitational force
By replacing Wp=Fh1 and Wg=mgh2, being h1 the distance of the motion of the hand and h2 the distance of the yo-yo, m is the mass of the yo-yo, then you obtain:

the change in the translational kinetic energy is 0.138J
b) the new speed of the yo-yo is obtained by using the previous result and the formula for the kinetic energy of an object:

where vf is the final speed, vo is the initial speed. By doing vf the subject of the formula and replacing you get:

the new speed is 3.58m/s
c) in this case what you can compute is the quotient between the initial rotational energy and the final rotational energy

hence, the change in Er is about 1.52J times the initial rotational energy
Electro waves in a vacuum air is deals with this and electricity when the air and the electricity it makes electro magnets.
(a) The gas of interstellar medium can be detected from the radiations of photons of wavelength 21 cm.
(b) The gas of interstellar medium can be detected from the absorption lines present in the light from distant stars, which must be caused by a medium of density and temperature other than that of the stars emitting the lights.
<h3>
What is interstellar medium?</h3>
Interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy.
<h3>Evidence that interstellar medium contains both gas and dust</h3>
- The gas of interstellar medium can be detected from the radiations of photons of wavelength 21 cm.
- The gas of interstellar medium can be detected from the absorption lines present in the light from distant stars, which must be caused by a medium of density and temperature other than that of the stars emitting the lights.
Learn more about interstellar medium here: brainly.com/question/4173326
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Answer:

Explanation:
assume
M= mass of Mars
m=mass of phobos
r=orbital radius
T=period
we can apply F=ma to this orbital motion (considering the cricular motion laws)
where,
and a=rω^2
where ω=
and G is the universal gravitational constant.
G = 6.67 x 10-11 N m2 / kg2
