3. 5 m A D с B 0.5 m 1.3 m Figure 2 A beam ADCB has length 5 m. The beam lies on a horizontal step with the end A on the step and the end B projecting over the edge of the step. The edge of the step is at the point D where DB = 1.3 m, as shown in Figure 2. When a small boy of mass 30 kg stands on the beam at C, where CB = 0.5 m, the beam is on the point of tilting. The boy is modelled as a particle and the beam is modelled as a uniform rod. (a) Find the mass of the beam. (3) A block of mass X kg is now placed on the beam at A. The block is modelled as a particle. (b) Find the smallest value of X that will enable the boy to stand on the beam at B without the beam tilting. (3) (c) State how you have used the modelling assumption that the block is a particle in your calculations. (1)

answer: i don't know the answer good luck

explanation:

-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

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.