A rock of mass m is dropped to the ground from a height h. A second rock, with mass 2m, is dropped from the same height. Ignoring air resistance, when the second rock strikes the ground, its kinetic energy is.1. Twice that of the first rock2. Four times that of the first rock3. The same as that of the first rock4. Half as much as that of the first rock5. Impossible to determine

Gravity is the universal force of attraction between a free-falling objects and the Earth. The objects falling from the same height will have the same speed.

The correct answer is:

Option 1.  Twice that of the first rock.

Air resistance has been ignored in the given situation. The rocks when dropped from the same height will have the same speed and acceleration. The kinetic energy of rocks with different masses can be given as:

From the above equation of kinetic energy, it can be predicted that the speed is same for the rocks. The kinetic energy is directly dependent on the mass, such that the rock with a mass of 2m will have more kinetic energy.

Thus, the kinetic energy of the rock with a mass of 2m will be twice that of the first rock.

To know more about kinetic energy, refer to the following link:

link

1. Twice that of the first rock.

Explanation:

It is first important to realize that without air resistance, all objects dropped from the same height will travel at the same speed. This is because the acceleration of each object is the same, since gravity acting on each object is the same.

This means that the first and second rock strike the ground at the same speed, since they were released from the same height.

Kinetic energy = 0.5 * mass * Speed^2

Since the speed in the above equation is the same for both objects, the kinetic energy just depends on the mass of the object. If mass is increases 2 times in the above equation, Kinetic energy will also increase two times.

Thus, the second rock's kinetic energy is twice that of the first rock.

-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