What causes the rider on a roller coaster to experience the + or - g’s if gravity always remains the same on earth

Yes both = and - g can be felt by a rider in a roller coaster.

Explanation:

It is crucial to understand how we feel gravity in this case.

We humans have no sensory organs to directly detect magnitude and direction like some birds and other creatures, but then how do we we feel gravity?

When we stand on our feet we feel our weight due to the normal reaction of floor on our feet trying to keep us stand and our weight trying to crush us down. In an elevator we feel difference in our weight (difference magnitudes of gravity) but actually we are feeling the differences in normal reactions under different accelerations of the elevator.

In the case of roller coaster you will feel +g as you  sit on a chair in it, but will feel -g when you are in upside down position as roller coaster move.

When you are seated you will feel the normal reaction of seat on you giving you the feeling +g and the support of the buckles to stay in the roller coaster when you are upside down will give you the -g feeling.

This is just the physics approach, a biological approach can be given in association with sensors relating to ears.

-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

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