El trabajo hecho por la gravedad durante el descenso de un proyectil es:

a) positivo.

b) negativo.

c) cero.

d) depende de la dirección del eje y.

e) depende de la dirección del eje x.

Explanation:

The question is

The work done by gravity during a projectile decline is:

a) Positive.

b) Negative.

c) Zero.

d) Depends on y-axis direction.

e) Depends on x-axis direciton.

Remember that Work is defined as the energy needed to move an object. Mathematically, it's the product between the force exerted and the displacement. That means if we don't have any displacement, then there's no work.

In this case, we are talking about the work done by the gravity force. When a projectile goes down, it's because of the gravity force, which means it can't be zero.

Specifically, the work done by gravity is positive, because when the projectile is going down, it's getting closer to the atracttive mass, which is Earth.

Therefore, the right answer is a.

-first use of geothermal energy occurred more than 10,000 years ago in north america by american paleo-indians

-the first industrial use of geothermal energy began near pisa, italy in late 18th century

-in 1904, italian scientist piero ginori conti invented the first geothermal electric power plant in which steam was used to generate the power

-with the above experiment, the first geothermal plant in usa started in 1922 with a capacity of 250 kilowatts

-however, in 1946 first ground-source geothermal heat pump installed at commonwealth building in portland, oregon

-during the 1960’s, pacific gas and electric began operation of first large scale geothermal power plant in san francisco, producing 11 megawatts

-in 1973, when oil crisis began many countries began looking for renewable energy sources and by 1980’s geothermal heat pumps (ghp) started gaining popularity in order to reduce heating and cooling costs

-as effect of climate change started showing results, governments of various countries joined hands to fight against it, for which kyoto protocol was signed in japan in 1997, laid out emission targets for rich countries and required that they transfer funds and technology to developing countries, 184 countries have ratified it

hope this

report!

explanation:

physics means: "the branch of science concerned with the nature and properties of matter and energy. the subject matter of physics, distinguished from that of chemistry and biology, includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms."