Two students are on a balcony a distance h above the street. one student throws a ball vertically downward at a speed vi; at the same time, the other student throws a ball vertically upward at the same speed. answer the following symbolically in terms of vi, g, h, and t. (take upward to be the positive direction.)
(a) what is the time interval between when the first ball strikes the ground and the second ball strikes the ground?
δt =

(b) find the velocity of each ball as it strikes the ground.
for the ball thrown upward vf =
for the ball thrown downward vf =

(c) how far apart are the bal

-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