We will examine the physics of collisions from the point of view of the traffic cop situation you are called to the site of a collision between a small car and a half ton truck on a lonely country road. you are given the following information a) on clean dry pavement at a temperature of 20 c, the coefficient of kinetic friction is 0.600 on locked wheels. b) the truck has left a skid mark that is 25.7 m long c) the car has left a skid mark that is 20.3 m long d) the estimated mass of the truck and contents was 1250 kg e) the estimated mass of the car and contents was 750 kg f the truck's skid mark is due north g) the car's skid mark is due east h) the debris travelled 10.6 m 18.4 degrees e of n i) the collisions appear to have been completely inelastic j) the speed limit was 90 km/hr k) miraculously no one was seriously hurt from this data can you work out the speed of the two vehicles prior to breaking (i. e. before the skid marks)?

-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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