A hiker walks 7.7 miles to the east in 3.6 hours, then turns around and walks 2.1 miles to the west in 2.4 hours. What was the magnitude of her average velocity during the trip?

2.18 miles per hour

Explanation:

Given:

A hiker walks 7.7 miles to the east in 3.6 hours.

A hiker walks 2.1 miles to the west in 2.4 hours

To find: magnitude of average velocity during the trip

Solution:

Total distance = 7.7 + 2.1 = 9.8 miles

Total Time = 2.1 + 2.4 = 4.5 hours

Average velocity = Total distance ÷ Total Time = miles per hour

think its the third option

-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